US20110160614A1

US20110160614A1 - Blood test apparatus

Info

Publication number: US20110160614A1
Application number: US13/043,972
Authority: US
Inventors: Masaki Fujiwara; Toshihiro Akiyama; Yoshinori Amano
Original assignee: Panasonic Corp
Current assignee: PHC Corp
Priority date: 2006-01-05
Filing date: 2011-03-09
Publication date: 2011-06-30
Also published as: CN102415888A; WO2007077930A1; EP1961382A4; EP1961382A1; US20090281455A1; CA2635980C; US7927290B2; KR20080073782A; KR101010797B1; JPWO2007077930A1; CN101346101B; CA2635980A1; CN101346101A; JP4956443B2

Abstract

A blood sampling cartridge is attachable to and removable from an attaching part of a blood test apparatus that includes a housing. The attaching part is provided in one side of the housing. The blood sampling cartridge includes a holder, a blood sensor that is attachable to one end of the holder, a lancet that is movable inside the holder, a blood collection needle attached to one end of the lancet, and a guide provided on the lancet. The guide of the lancet is configured to latch with the holder after puncturing with the blood collection needle, such that the blood collection needle is prevented from projecting beyond the blood sensor.

Description

CROSS-REFERENCE TO RELATED APPLICATIONS

This is a continuation of U.S. application Ser. No. 12/159,904 filed Jul. 2, 2008, which was the National Stage of International Application No. PCT/JP2006/326262, filed Dec. 28, 2006.

TECHNICAL FIELD

The present invention relates to a blood sampling cartridge. More particularly, the present invention relates to an apparatus measuring the blood sugar level in blood.

BACKGROUND ART

Diabetes patients need to measure the blood sugar level (glucose level) regularly, and inject insulin based on the blood sugar level to maintain a normal blood sugar level. To maintain the normal blood sugar level, diabetes patients need to measure the blood sugar level frequently, sample a small amount of blood from fingertips of the Patients using a blood test apparatus, and measure the blood sugar level of the sampled blood.
FIG. 28 shows an example of the conventional blood test apparatus (see Patent Document 1). Blood test apparatus 1 has cylindrically-shaped housing 2, plunger 3 that moves back and forth inside housing 2, lancet 4 that has one end 4 a held by plunger 3 and the other end 4 b attached with blood collection needle 5, and blood sensor (hereinafter “sensor”) 6 attached to one end 2 a of housing 2.
Sensor 6 of blood test apparatus 1 is made to abut on skin 7 of the patient. Latch between convex part 9 a of handle 9 connected to plunger 3 and concave part 2 b formed on housing 2 is disengaged. Plunger 3 urged by spring 10 is thereby propelled in the direction of arrow 8. Lancet 4 held by plunger 3 and blood collection needle 5 attached to the lancet 4 are also propelled in the direction of arrow 8.
Blood collection needle 5 that is propelled forward goes through sensor 6 and makes a tiny prick on skin 7. The blood flowing out from the prick is detected by a detecting section of sensor 6, converted to an electric signal, and led to connection electrode 6 a. Connection electrode 6 a is connected with measuring circuit 12 via connector 11. Measuring circuit 12 calculates the blood sugar level of the sampled blood and the calculation result is displayed on display section 13.
Further, a body fluid measuring apparatus that has an apparatus body and an attachment with a sensor and a blood collection needle, is reported (see Patent Document 2).
Patent Document 1: Japanese Patent Application Publication No. 2003-524496
Patent Document 2: Japanese Patent Application Laid-Open No. 2000-000231

DISCLOSURE OF INVENTION

Problems to be Solved by the Invention

However, above-described blood test apparatus 1 needs to attach lancet 4 to which blood collection needle 5 is attached, to plunger 3 as preparation before use and attach sensor 6 to one end 2 a of housing 2, and this work is troublesome.
This preparatory work will be further described. First, used sensor 6 attached to blood test apparatus 1 is removed. Next, plunger 3 is moved forward to one end 2 a of housing 2. Lancet 4, to which new blood collection needle 5 is attached, is then attached to plunger 3. Next, plunger 3 is moved backward, and blood collection needle 5 is pulled inside housing 2. In a state where blood collection needle 5 is pulled inside housing 2, new sensor 6 is attached to one end 2 a of housing 2. In this way, preparation is not completed until such many manipulation steps are performed.
Further, the body fluid measuring apparatus that has an apparatus body and an attachment with a sensor and a blood collection needle, disclosed in Patent Document 2, is not discussed sufficiently towards practical use. For example, device for attaching an attachment to an apparatus body; device for puncturing the skin with a puncturing body (blood collection needle) stably; and mechanism for leading sampled blood to the sensor efficiently, are not discussed. Therefore, the body fluid measuring apparatus is not practical.
The present invention provides a blood test apparatus that makes it possible to attach and remove a blood collection needle and a blood sensor in a simple manner, and an apparatus that alleviates the load and pain of the patient.

Means for Solving the Problem

In the blood test apparatus of the present invention, a holder, lancet, blood collection needle and blood sensor are integrated as a blood sampling cartridge which can be inserted to and removed from the apparatus detachably, and, when the blood sampling cartridge is attached, a plunger included in the apparatus holds the lancet, and connectors included in the apparatus are arranged so as to contact with the blood sensor.

ADVANTAGEOUS EFFECT OF THE INVENTION

As described above, according to the present invention, a blood sampling cartridge is formed with a lancet, a blood collection needle and a blood sensor in an integrated manner, so that it is possible to change the blood collection needle and the blood sensor in a simple manner. Further, the plunger of the blood test apparatus holds the lancet, and so, when the skin is punctured with the blood collection needle, the blood collection needle does not wobble and enables high linearity of movement, so that it is possible to puncture the skin with the blood collection needle stably. Still further, after sampling blood, the blood collection needle can move straight backward from the puncturing part and come to a stop. Therefore, the pain of the patient upon sampling blood can be alleviated to a minimum. That is, the plunger holds the lancet, and so a mechanism for preventing the blood collection needle from puncturing the patient's skin several times or a mechanism for adjusting the depth of puncturing, can be realized in a simple manner. By providing such a prevention mechanism and adjustment mechanism to the blood test apparatus instead of providing them to the blood sampling cartridge, it is possible to realize a smaller and lower-cost blood sampling cartridge.
Further, when the blood sampling cartridge is attached, the blood collection needle is accommodated in a holder, so that the blood sampling cartridge can be changed securely without hurting the patient with the blood collection needle, and the patient does not feel fear. Furthermore, the blood collection needle does not allow direct touch to skin, and so is sanitary. Further, every time a test is performed, the blood sensor and the blood collection needle are changed together, and so the blood collection needle can not be used several times, and there is no fear of infection.

BRIEF DESCRIPTION OF DRAWINGS

FIG. 1 is a cross-sectional view of a blood test apparatus;

FIG. 2A is an assembly drawing of a blood sampling cartridge forming the blood test apparatus;

FIG. 2B is an assembly drawing of the blood sampling cartridge having a second holder;

FIG. 2C is an assembly drawing of the blood sampling cartridge having a cap;

FIG. 2D is an assembly drawing of the blood sampling cartridge having the second holder and the cap;

FIG. 3A is a diagrammatic perspective view of the blood sampling cartridge;

FIG. 3B is a diagrammatic perspective view of the blood sampling cartridge having the second holder;

FIG. 4A is a cross-sectional view of the blood sampling cartridge with a cap;

FIG. 4B is a cross-sectional view of the blood sampling cartridge with the second holder and the cap;

FIG. 5A is a cross-sectional view of the blood sampling cartridge upon puncturing;

FIG. 5B is a cross-sectional view of the blood sampling cartridge after puncturing is finished;

FIG. 6 is a plan view that expands the main part of a guide for inserting the blood sampling cartridge into an attaching part;

FIG. 7 is a cross-sectional view of the attaching part into which the blood sampling cartridge is inserted;

FIG. 8A is a cross-sectional view showing a state where the blood sampling cartridge is attached to the attaching part of the blood test apparatus, particularly, showing a state where a blood sensor of the blood sampling cartridge contacts with a connector of the blood test apparatus; a state where a holder of the blood sampling cartridge and a housing of the blood test apparatus are connected via a sealing material;

FIG. 8B shows a state in detail where the holder of the blood sampling cartridge and the housing of the blood test apparatus are connected;

FIG. 8C shows a state in detail where the holder of the blood sampling cartridge and the housing of the blood test apparatus are connected;

FIG. 8D shows a state in detail where the holder of the blood sampling cartridge and the housing of the blood test apparatus are connected;

FIG. 8E shows a state in detail where the holder of the blood sampling cartridge and the housing of the blood test apparatus are connected;

FIG. 9A is a cross-sectional view of the blood sensor;

FIGS. 9B and 9C are cross-sectional views of the blood sensor having a bank provided on a substrate;

FIG. 9D is a cross-sectional view of the blood sensor having a hole provided on a cover in advance for allowing the blood collection needle to pass through;

FIG. 9E is a cross-sectional view of the blood sensor, part of the member being formed with a transparent member;

FIG. 10A is a plan view of the cover of the blood sensor;

FIG. 10B is a plan view of a spacer of the blood sensor;

FIG. 10C is a plan view of a substrate of the blood sensor;

FIG. 11A is a plan view of the cover of the blood sensor;

FIG. 11B is a plan view of the spacer of the blood sensor;

FIG. 11C is a plan view of the substrate of the blood sensor, to which the bank is provided;

FIG. 12A and FIG. 12B show manufacturing process of the substrate on which the bank is provided;

FIG. 13 shows a ring member for forming the bank on the substrate;

FIGS. 14A to 14C are plan views that disassemble the blood sensor, part of the base plate being formed with transparent material;

FIG. 14A is a plan view of the cover formed with transparent material, of the blood sensor (where a hole, which becomes a storing part, is formed);

FIG. 14B is a plan view of the spacer of the blood sensor;

FIG. 14C is a plan view of the substrate of the blood sensor;

FIG. 15 is a perspective plan view of the blood sensor and shows arrangement of electrodes, and the like;

FIG. 16 is a perspective plan view of another example of the blood sensor and shows arrangement of electrodes, and the like;

FIG. 17 is a perspective plan view of still another example of the blood sensor and shows arrangement of electrodes, and the like;

FIG. 18 shows a principle of glucose measurement in blood, of the blood test apparatus;

FIG. 19 is a characteristic diagram of glucose measurement;

FIG. 20A shows a relationship between the blood sensor and the operation of the blood collection needle;

FIG. 20B shows a relationship between the blood sensor to which the bank is provided and the operation of the blood collection needle;

FIG. 21A is a cross-sectional view showing a state of the lancet before puncturing in a state where the blood sampling cartridge is attached to the blood test apparatus;

FIG. 21B is a cross-sectional view showing a state of the lancet upon sampling blood;

FIG. 21C is a cross-sectional view showing a state of the lancet after sampling blood;

FIG. 22 shows a flow of glucose measurement using the blood test apparatus;

FIG. 23 is a block diagram of the blood test apparatus;

FIG. 24 is a block diagram of the blood test apparatus having a negative pressure means;

FIG. 25A is a cross-sectional view of the blood test apparatus having the negative pressure means;

FIG. 25B is a cross-sectional view of another blood test apparatus having the negative pressure means;

FIG. 26 is a cross-sectional view near the blood sensor of the blood test apparatus having the negative pressure means;

FIG. 27 shows a state of use of the blood test apparatus; and

FIG. 28 is a cross-sectional view of the conventional blood test apparatus.

BEST MODE FOR CARRYING OUT THE INVENTION

An Overview of the Blood Test Apparatus

The blood test apparatus according to the present invention has: (1) a housing; (2) a measuring circuit that is accommodated in the housing; (3) two or more connectors that are electrically connected to the measuring circuit; (4) an attaching part that is formed in one side of the housing; (5) a plunger that moves back and forth in the housing; (6) a lancet, one end of which is held by the plunger so as to allow the one end to be inserted and removed; (7) a blood collection needle that is attached to the other end of the lancet; (9) a holder that is inserted and fixed inside the attaching part, and inside which the lancet can move; and (10) a blood sensor that is attached to one end of the holder and that has two or more connection electrodes.
FIG. 1 shows a cross-sectional view of an example of the blood test apparatus of the present invention. Blood test apparatus 20 in FIG. 1 has housing 21 formed with resin. Housing 21 is a frame of the apparatus and accommodates primary members of the apparatus.
Housing 21 accommodates measuring circuit 32. The measuring circuit is a member that receives a detection result of blood components by a blood sensor (described later) and measures the blood components. Information detected by the blood sensor is sent to measuring circuit 32 through connector 27, terminal 33, and the like. One side of housing 21 is cylindrically-shaped attaching part 21 a. Through end 21 b of attaching part 21 a, blood sampling cartridge 22 is inserted. Positioning concave part 21 h provided on the attaching part 21 a and positioning convex part 23 h provided in holder 23 on the blood sampling cartridge 22 are engaged, and thereby blood sampling cartridge 22 inserted to attaching part 21 a is fixed to a predetermined position in attaching part 21 a.
Blood sampling cartridge 22 has: cylindrically-shaped holder 23; blood sensor 24 that is attached to one end 23 a of holder 23; lancet 25 that can slide in holder 23 freely; and blood collection needle 26 that is attached to the other end 25 b of lancet 25. Blood sensor 24 includes a test electrode and a connection electrode connected to the test electrode. Connector 27 contacts with the connection electrode.
Grip part 25 f formed near one end 25 a of lancet 25 which is one member of blood sampling cartridge 22, is held by holding part 30 a provided at one end of plunger 30 that slides inside attaching part 21 a. Plunger 30 holds lancet 25, so that, when the skin is punctured with blood collection needle 26, blood collection needle 26 does not wobble and enables high linearity of movement, so that it is possible to puncture the skin with blood collection needle 26 stably.
On the other hand, the other end 30 b of plunger 30 is connected to one end 31 a of handle 31 formed in the shape of a crank. Latch convex part 31 c is formed at the other end 31 b of handle 31. Handle 31 goes through hole 21 c formed in housing 21 and is latched by the joint of latch convex part 31 c and latch concave part 21 d.
As the drive mechanism of plunger 30, for example, the method disclosed in Japanese Patent Application Laid-Open No. 2006-314718 can be adopted. According to this method, a puncturing needle can move straight backward and come to a stop after puncturing, so that it is possible to alleviate the pain of the patient upon puncturing to a minimum, and, further, realize a mechanism for preventing the blood collection needle from puncturing the patient's skin several times and a mechanism for adjusting the depth of puncturing, in a simple manner. By providing such a prevention mechanism and an adjustment mechanism on the blood test apparatus, instead of providing on the blood sampling cartridge, it is possible to realize a smaller and lower-cost blood sampling cartridge.
An example of a mechanism for preventing a blood collection needle from puncturing the patient's skin several times, is disclosed in Japanese Patent Application Laid-Open No. 2006-314718.
A pull spring, one end of which is fixed, has the other end hooked on a lever for which rotation is partially limited and which is provided in the plunger. A forward force is given to the plunger by a contracting and restoring force of the pull spring. The plunger moves on by inertia to pass the position where the forward force is no longer given. In this case, the pull spring is extended and the plunger is given a force towards the rear end by the restoring force. In this way, by configuring an urging means that gives a force towards the front end and a force towards the rear end to the plunger, with one pull spring, manufacturing process of a puncturing tool is simplified and a puncturing needle is prevented from puncturing the patient's skin several times (see unexamined patent publication).
As an example of the mechanism for adjusting the depth of puncturing, when the plunger moves in the direction of the axis, puncturing depth adjusting knob 84 that has a receiving part which limits the amount of the move, is jointed rotatably (see FIG. 27). The receiving part (not shown) of puncturing depth adjusting knob 84 has a helical shape. By rotating adjusting knob 84 with respect to attaching part 21 a of housing 21, it is possible to change the amount of the move of the plunger in the direction of the axis.
As described above, measuring circuit 32 is stored inside housing 21 on the other end 21 e side. Measuring circuit 32 is connected to terminal 33 formed in attaching part 21 a. Further, terminal 33 is connected to connector 27. Terminal 33 is configured with two or more (usually, four or five) terminals 33 a to 33 d (or 33 e) and connected to corresponding connectors 27 a to 27 d (or 27 e). As described above, connectors 27 contact with relevant connection electrodes, respectively.
The housing accommodates battery 34 that supplies power to measuring circuit 32.
As described above, blood test apparatus 20 has blood sampling cartridge 22 that is integrated with built-in lancet 25 with blood collection needle 26 attached and built-in blood sensor 24, and blood sampling cartridge 22 can be attached to and removed from attaching part 21 a. Therefore, the whole of blood sampling cartridge 22, including the blood collection needle and the blood sensor, can be changed in a simple manner. Further, blood sensor 24 and blood collection needle 26 are changed together every test, so that there is no fear that blood collection needle 26 is used several times and there is no threat of infection.
Blood collection needle 26 of blood sampling cartridge 22 is accommodated in holder 23 upon attachment, so that blood collection needle 26 does not hurt the patient and is secure and does not make the patient feel fear. Further, blood collection needle 26 accommodated in holder 23 does not allow being touched directly, and so is sanitary.

[The Blood Sampling Cartridge]

FIG. 2 is a diagrammatic perspective view of assembly of an example of a blood sampling cartridge. Blood sampling cartridge 22-1 shown in FIG. 2A has holder 23, blood sensor 24, lancet 25 and blood collection needle 26. Lancet 25 and blood collection needle 26 are formed in an integrated manner so as not to disjoin easily. On the other hand, holder 23 and lancet 25 may be integrated after being manufactured separately, and may be separable from each other.
Blood sampling cartridge 22-2 shown in FIG. 2B further has second holder 38, blood sampling cartridge 22-3 shown in FIG. 2C further has cap 39, and blood sampling cartridge 22-4 shown in FIG. 2D further has second holder 38 and cap 39.
Blood sensor 24 is attached to one end 23 a of holder 23 and examines the blood sampled by puncturing using blood collection needle 26.
A cross section of holder 23 on the side where the blood sensor 24 is attached has a cross shape. Connectors 27 (in the blood test apparatus) formed with conductive metal are guided between convex parts 23 c of a cross shape, and connectors 27 each contact with the connection electrodes of blood sensor 24. The other end side 23 b of holder 23 has convex parts 23 d formed integrated with convex parts 23 c. Holes 23 e are provided at convex parts 23 d.
Lancet 25 is inserted in holder 23. Lancet 25 has guides 25 c for preventing reuse and guides 25 d for improving linearity, which are provided in an integrated manner. As shown in FIG. 2A, two guides 25 c and two guides 25 d are provided. Each of two guides 25 c and each of two guides 25 d face each other 180 degrees apart.
Guides 25 d of lancet 25 are provided so as to slide in holes 23 e provided in convex parts 23 d of holder 23. Convex parts 25 e are provided near one end 25 a of lancet 25. Between convex part 25 e and one end 25 a, grip part 25 f is provided.
Second holder 38 of blood sampling cartridge 22-2 shown in FIG. 2B has circular projecting part 38 a abutting on the skin of the patient. Preferably, the inner diameter of projecting part 38 a is approximately 4 to 15 mm (more preferably 5 to 7 mm), and the height of the projecting part is approximately 0.5 to 5 mm (more preferably 1 to 2 mm). When projecting part 38 a abuts on the skin, the skin is plumped up, so that the blood can be sampled more easily. Further, by applying a negative pressure inside of projecting part 38 a, the skin can be in close contact with sensor 24, and so the depth of puncturing using blood collection needle 26 can be adjusted more easily. And projecting part 38 a has a circular and projecting shape, so that a negative pressure can be applied reliably. As a result, the blood can be sampled reliably to be brought to the sensor after puncturing.
Although, in FIG. 2B, circular projecting part 38 a is provided in the second holder, the projecting part only has to be a concave part that forms space between the skin and blood sensor 24.
Cap 39 of blood sampling cartridge 22-3 shown in FIG. 2C is used to protect blood sensor 24 and fix lancet 25 of blood sampling cartridge 22-3 before attachment. That is, as shown in FIG. 4A, cap 39 passes through sensor 24 and can be connected to lancet 25. Further, cap 39 can be connected with lancet 25 so as to encompass blood collection needle 26 attached to lancet 25, so that it is possible to keep sterile blood collection needle 26 sanitary.
Further, in case where cap 39 is fixed to lancet 25, when blood sampling cartridge 22-3 is attached to the apparatus, it is possible to attach lancet 25 to holding part 30 a (see FIG. 1) in a simple and reliable manner.
Blood sampling cartridge 22-4 shown in FIG. 2D has both second holder 38 included in blood sampling cartridge 22-2 and cap 39 included in blood sampling cartridge 22-3, and so has the benefits of both. FIG. 4B is a cross-sectional view of blood sampling cartridge 22-4.
FIG. 3 is a diagrammatic perspective view of blood sampling cartridge 22.
In blood sampling cartridge 22-1 shown in FIG. 3A, the height of cross-shaped convex part 23 c formed on the one end side 23 a (blood sensor side) of holder 23 is higher than the height of cross-shaped convex part 23 d formed on the other end side 23 b of holder 23. That is, the convex part side 23 d of holder 23 is thinner than the convex part side 23 c. In this way, the front part of the holder of the blood sampling cartridge with respect to the insertion direction is thinner than the rear part, so that blood sampling cartridge 22 can be inserted to attaching part 21 a readily.
Further, tip part 23 g on the side 23 b of convex part 23 d projects at an acute angle. This is important to make sure that connector 27 formed on the attaching part side 21 a contacts with a desired position of blood sensor 24.
The whole of blood sampling cartridge 22-1 can be attached to and removed from attaching part 21 a, and so blood collection needle 26 and blood sensor 24 can be attached to and removed from attaching part 21 a together. Therefore, blood sensor 24 and blood collection needle 26 can be attached and changed in a simple manner.
Blood sampling cartridge 22-2 shown in FIG. 3B is the same as blood sampling cartridge 22-1 shown in FIG. 3A except that blood sampling cartridge 22-2 has second holder 38 (see FIG. 2B) that covers blood sensor 24.
FIG. 5A is a cross-sectional view of blood sampling cartridge 22 upon puncturing, and FIG. 5B is a cross-sectional view of blood sampling cartridge 22 when puncturing is finished.
As shown in FIG. 5A, upon puncturing, blood collection needle 26 projects from blood sensor 24 and comes to a stop. At this time, convex part 25 e of lancet 25 is latched at latch part 23 f provided at the other end 23 b of holder 23. Therefore, blood collection needle 26 does not project further from the blood sensor. As shown in FIG. 5B, when puncturing is finished, blood collection needle 26 is accommodated in holder 23 and comes to a stop. The roots of guides 25 c of lancet 25 are latched at latch part 23 f provided at the other end 23 b of holder 23. Therefore, lancet 25 does not fall off from holder 23.
In the state shown in FIG. 5B, blood sampling cartridge 22 is removed from attaching part 21 a. In the state shown in FIG. 5B, even if lancet 25 is pushed in the direction of arrow 35 by error, guides 25 c run onto convex parts 23 c from holes 23 e of holder 23 by their elasticity. The bases of guides 25 c are then latched at the ends of holes 23 e and come to a stop, and so blood collection needle 26 does not project from blood sensor 24 again and is secure and does not make the patient feel fear.
FIG. 6 is a plan view that expands the main part of guide 36 for inserting blood sampling cartridge 22 to attaching part 21 a. Guide 36 is formed with convex part 21 f provided on the internal surface of attaching part 21 a and convex part 23 d provided on the external surface of the holder. Tip part 21 g of convex part 21 f and tip part 23 g of convex part 23 d are preferably formed to have a sharp angle.
Convex part 21 f and convex part 23 d face each other when blood sampling cartridge 22 is inserted into attaching part 21 a, and control the rotation angle with respect to the axis of the direction of inserting the blood sampling cartridge, adequately. That is, when blood sampling cartridge 22 is inserted into attaching part 21 a, even when the rotation angle with respect to the axis of the insertion direction, is off from a desired position, as shown by arrow 37, blood sampling cartridge 22 is inserted along guide 36 while the rotation angle with respect to the axis is corrected. By this means, connector 27 provided at attaching part 21 a is made to contact with a desired position (contact part of the connection electrode) of blood sensor 24 of blood sampling cartridge 22 reliably.
FIG. 7 is a cross-sectional view showing a state where blood sampling cartridge 22 is attached to inside of attaching part 21 a. As described above, blood sampling cartridge 22 is guided by guide 36 and inserted, and, as shown in FIG. 7, convex part 21 f and convex part 23 c are engaged, and thereby blood sampling cartridge is fixed at a specific angle (angle at which connectors 27 abut on terminals 33) specified in attaching part 21 a. This is important to deliver signals of blood sensor 24 to measuring circuit 32 reliably.
The outer periphery of blood sampling cartridge 22 or the inner periphery of attaching part 21 a does not have to be round and may be an elliptic or a polygonal. If the outer periphery of blood sampling cartridge 22 or the inner periphery of attaching part 21 a is round or regular polygon, blood sampling cartridge 22 can be inserted at an arbitrary rotation angle with respect to the axis of the insertion direction, so that the insertion is facilitated.
It is also possible to make the cross sections of blood sampling cartridge 22 and attaching part 21 a asymmetrical and insert blood sampling cartridge 22 only in a fixed direction. For example, it is also possible to form a convex part at part of blood sampling cartridge 22, form a concave groove at attaching part 21 a matching the convex part, and fit in the convex part along this groove.
[The State where the Blood Sampling Cartridge is Attached to the Blood Test Apparatus]
FIG. 8A is a cross-sectional view of a state where blood sampling cartridge 22-4 shown in FIG. 4B is attached to attaching part 21 a of blood test apparatus 20.
Second holder 38 of blood sampling cartridge 22-4 and housing 21 of blood test apparatus 20 join together via seal material 55. Seal material 55 may be provided in either blood sampling cartridge 22-4 or the blood test apparatus. The airtightness inside the apparatus is improved by seal material 55. By improving the airtightness, upon blood sampling, it is possible to apply a negative pressure (described later) near the puncturing position in the apparatus more simply, sample the blood after puncturing quickly and reliably, improve the stability and reliability of the measuring test, reduce the amount of sampled blood, and reduce the load on the patient substantially.
Further, in FIG. 8A, blood sensor 24 which contacts with connector 27 of the blood test apparatus, is supported by second holder 38, so that the contact pressure between connector 27 and blood sensor 24 becomes stable.
In FIG. 8A, seal material 55 is sandwiched between second holder 38 of blood sampling cartridge 22-4 and an end of housing 21 of blood test apparatus 20. On the other hand, FIG. 8B and FIG. 8D show a mechanism of locking blood sampling cartridge 22-4 in housing 21. That is, not only by sandwiching seal material 55, but also by making locking claw (moving side) 28 a provided in holder 38 of blood sampling cartridge 22-4 and locking claw (fixed side) 28 b provided in housing 21 fit in, blood sampling cartridge 22-4 is locked. A pressure is applied to seal material 55 from both, and the position of blood sampling cartridge 22-4 is thereby fixed, so that the airtightness inside the apparatus improves and the stability improves significantly.
Locking claw 28 a on the moving side or locking claw 28 b on the fixed side only have to be provided at either holder 38 of blood sampling cartridge 22-4 or housing 21 of apparatus 20, and the same effect can be obtained.
Locking is released in a simple manner with, for example, push button 29 a (see FIG. 8C) or slide button 29 b (see FIG. 8E), provided on the housing 21, and workability of the releasing is good. It is also possible to use electric and pneumatic drive of an electromagnetic valve instead of the push button. Of course, it is also possible to add rubber or other seal material 29 c to maintain the seal effect at space and the moving part near the locking member.

[The Blood Sensor]

As described above, blood sampling cartridge 22 has blood sensor 24.
Blood sensor 24 has: a base plate; a storing part provided on the base plate; a supply channel, one end of which communicates with the storing part; a detecting section provided in the supply channel; and an air hole that communicates with the supply channel. One surface of the base plate abuts on the skin to be punctured, and the hole formed on the substrate surface which abuts on the skin is an opening part of the storing part. The blood flowing out from the skin by puncturing is led to the storing part from the opening part.
FIG. 9A is a cross-sectional view of blood sensor 24-1, which is an example of the blood sensor. Blood sensor 24-1 has substrate 41, spacer 47 stacked on the upper surface of substrate 41, and cover 48 stacked on the upper surface of spacer 47. Hole 41 c provided in substrate 41 and hole 47 c provided in spacer 47 form blood storing part 49. Supply channel 47 d is connected to storing part 49. The tip of supply channel 47 d is connected to air hole 48 c.
Reagent 50 is preferably placed on detecting section 40. Detecting section 40 will be described later, but, for example, is on detection electrodes 42 and 44 (described later) on substrate 41. Reagent 50 is selected as appropriate depending on the type of the blood component to be measured. When the glucose level is measured, reagent 50 is prepared by dropping in the detecting section reagent solution prepared by adding and dissolving PQQ-GDH (0.1 to 5.0 U/sensor), potassium ferricyanide (10 to 200 mM), maltitol (1 to 50 mM) and taurine (20 to 200 mM) to a 0.01 to 2.0 wt % aqueous solution of CMC, and drying the reagent solution.
Like blood sensors 24-2 and 24-3 shown in FIGS. 9B and 9C, on the skin contacting surface of substrate 41, bank 51 may be provided near hole 41 c. Bank 51 may be formed integrated with substrate 41 by press working, and the like (FIG. 9B), or may be formed with separate members (FIG. 9C). Bank 51 in FIG. 9C may be formed by pasting ring member 54 shown in FIG. 13 to hole 41 c. Ring member 54 is pasted so that hole 54 a of ring member 54 is continuous with substrate hole 41 c forming storing part 49. The diameter of substrate hole 41 c forming storing part 49 is preferably the same as the diameter of hole 54 a of ring member 54. The other members may be made the same as in blood sensor 24-1.
In FIG. 9B, storing part 49 is formed with lifting part 41 d and hole 41 c, which are provided in substrate 41, and hole 47 c provided in spacer 47.
The height of the bank is preferably 0.5 to 5 mm (more preferably, 1 to 2 mm). Bank 51 prevents sampled blood from flowing out without being led to storing part 49 of the blood sensor.
As in blood sensor 24-4 shown in FIG. 9D, hole 52 may be provided in cover 48. Blood collection needle 26 passes through hole 52. When hole 52 is provided in cover 48 in advance, it is not necessary to open a puncturing hole using puncturing needle 26, so that less force is required upon puncturing, and the damage of the needle tip of puncturing needle 26 is minimized.
As in blood sensor 24-5 shown in FIG. 9E, it is also possible to form storing part 49 with cover 48 and spacer 47 and form air hole 48 c in substrate 41. When cover 48 for blood sensor 24-5 is made a transparent member, it is possible to check whether blood is supplied to supply channel 47 d or detecting section 40 from outside.
FIG. 10 is a plan view that disassembles blood sensor 24. Blood sensor 24 has cover 48 shown in FIG. 10A, spacer 47 shown in FIG. 10B and substrate 41 shown in FIG. 10C.
FIG. 10C is a plan view of substrate 41. Although substrate 41 has an octagon shape, the shape of the substrate is not particularly limited. The material of substrate 41 is preferably resin such as polyethylene terephthalate (PET). The thickness of substrate 41 preferably falls within the range from 0.075 to 0.25 mm (preferably 0.188 mm).
On one surface of substrate 41 (surface that is pasted with spacer 47), detection electrodes 42 to 45 and connection electrodes 42 a to 45 a connected to detection electrodes 42 to 45, respectively, are formed in an integrated manner. Detection electrodes 42 to 45 and connection electrodes 42 a to 45 a are formed by forming a conductive layer through the sputtering method or the vapor deposition method, with gold, platinum, palladium as material and applying laser machining to this conductive layer. Hole 41 c is provided in approximately the center of substrate 41, and its diameter may be approximately 2.0 mm.
By using transparent material as material of substrate 41, and making the detection electrodes thin transparent films, it is possible to observe the blood in supply channel 47 readily.
FIG. 10B is a plan view of spacer 47. The thickness of spacer 47 may fall in a range of 0.05 to 0.15 mm (preferably 0.1 mm). Spacer 47 is preferably a polygonal (preferably a regular polygon) such as an approximate cross shape, because connector 27 (not shown) can be arranged easily in a dent of the cross-shape. Hole 47 c is provided at the position corresponding hole 41 c which is provided in approximately the center of spacer 47 on substrate 41. The diameter of hole 47 c may be made the same (2.0 mm) as the diameter of hole 41 c. Slit 47 d is formed in the direction from hole 47 c to cross-shaped first convex part 47 e and corresponds to the blood supply channel. By setting the width of the groove of slit 47 d 0.6 mm and setting the length in the flow channel direction 2.4 mm, the cavity of supply channel 47 d may be set approximately 0.144 μL. In this way, the test can be performed with a small amount of blood, so that the load on the patient becomes small, and the patient does not feel fear. The material of spacer 47 may be resin such as polyethylene terephthalate (PET).
FIG. 10A is a plan view of cover 48. Cover 48 has an approximate cross shape, air hole 48 c is provided at cross-shape first convex part 48 d so as to correspond to the tip part of supply channel 47 d. Preferably, the diameter of air hole 48 c is approximately 50 μm.
The material of cover 48 is plastic, and preferably polyethylene terephthalate. The thickness of cover 48 may fall in a range of 0.05 to 0.25 mm (preferably 0.075 mm).
FIG. 11 is a plan view that disassembles the blood sensor (see FIG. 9B and FIG. 9C) having a bank. FIG. 11A shows cover 48, FIG. 11B shows spacer 47, and FIG. 11C shows substrate 41-1 on which bank 51 is formed. The blood sensor shown in FIG. 11 is the same as blood sensor 24 shown in FIG. 10 except substrate 41-1, and so substrate 41-1 will be described.
FIG. 11C is a plan view of substrate 41-1 forming blood sensor 24, and substrate 41-1 has an octagon shape. Material of substrate 41-1 is polyethylene terephthalate (PET), and its thickness can fall in a range of 0.075 to 0.25 mm and is preferably 0.188 mm.
Like substrate 41 of FIG. 10C, on the surface of substrate 41-1, detection electrodes 42 to 45, and connection electrodes 42 a to 45 a led from detection electrodes 42 to 45, respectively, are formed in an integrated manner. Hole 41 c is provided in approximately the center of substrate 41-1, and the diameter of hole 41 c may be 1.5 mm.
Bank 51 is provided around hole 41 c of substrate 41-1. Blood sensor 24 is made by stacking spacer 47 on the reverse side of the surface where bank 51 is formed, and further, stacking cover 48 on the upper surface of spacer 47.
Substrate 41-1 is produced through press working (see FIG. 12), or produced with pasting ring member 54 to substrate 41 (see FIG. 13).
FIG. 12 shows a method of making substrate 41-1 on which bank 51 is formed in an integrated manner, through press working. FIG. 12A shows a state before bank 51 is formed. In FIG. 12A, concave mold 90 has circular hole 90 a. The diameter of circular hole 90 a may be approximately 1.55 mm. The upper part of circular hole 90 a opens upward at an angle of 45 degrees. The diameter of the upper part of the opening part may be approximately 2 mm.
Substrate 41 is mounted on the upper surface of concave mold 90. Further, convex mold 91 is set above substrate 41. On convex mold 91, circular convex part 91 a that projects downward, is provided. The diameter of base part 91 b of convex part 91 a is made approximately 2 mm, and the diameter of tip part 91 c is made approximately 1.5 mm. Base part 91 b and tip part 91 c are connected via 45-degree taper 91 d. Taper 91 d forms lifting part 41 d and bank 51.
By pressing convex part 91 a of convex mold 91 towards hole 90 a of concave mold 90, on which substrate 41 is mounted (see FIG. 12B), lifting part 41 d and bank forming part of storing part 49 can be formed on substrate 41 in an integrated manner.
FIG. 13 shows ring member 54 to be pasted to the lower surface of substrate 41. Ring member 54 has hole 54 a. It is also possible to stack spacer 47 and cover 48 after forming bank 51 by pasting ring member 54 to substrate 41, or paste member 54 to form bank 51 after stacking substrate 41, spacer 47 and cover 48. The material of member 54 is preferably the same material as substrate 41 or spacer 47 in terms of manufacturing control.
FIG. 14 is a plan view that disassembles blood sensor 24-5 (see FIG. 9E), part of the base plate being formed with a transparent member. FIG. 14A shows cover 48, FIG. 14B shows spacer 47, and FIG. 14C shows substrate 41.
In blood sensor 24-5 shown in FIG. 9E, substrate 41, spacer 47 and cover 48 are placed upside down with respect to blood sensor 24-1 shown in FIG. 9A. Therefore, detection electrodes are formed on the upper side of storing part 49, on substrate 41 shown in FIG. 14C. Hole 41 e is provided at substrate 41, and connection electrode 43 a passes through hole 41 e from detection electrode 43 and is led to the opposite side of the surface in contact with the skin. Further, air hole 48 c is also provided in substrate 41.
FIG. 14B shows spacer 47 and is the same as FIG. 10B.
FIG. 14A shows cover 48, and its material is preferably transparent material. When cover 48 is transparent, the blood sampled from the skin to the supply channel can be seen, which makes judgment as to whether or not the blood sampling cartridge is used more easily. In the center of cover 48, hole 48 f, which is part of the storing part, is formed.

[The Thickness of the Substrate, Spacer and Cover]

The thickness of substrate 41, spacer 47 and cover 48 of blood sensor 24, and its ratio are important for sampling the blood. First, to cause the capillary action in supply channel 47 d, the thickness of the spacer preferably falls within the range from 0.05 to 0.15 mm (preferably 0.1 mm).
Further, with blood sensors 24-1 to 24-4 shown in FIG. 9A to FIG. 9D, to adjust the volume of storing part 49 and supply channel 47, it is necessary to adjust the thickness of spacer 47 and the thickness of substrate 41. The thickness of the substrate is preferably the same as the thickness of the spacer or greater, and preferably falls within the range where the thickness of substrate 41: the thickness of spacer 47=1:1 to 5:1 (preferably, 2.5:1). Further, the thickness of cover 48 is preferably made less than the thickness of substrate 41 so that the total thickness of blood sensor 24 is preferably made thin. Therefore, the thickness of substrate 41: the thickness of spacer 47: the thickness of cover 48 may be 2.5:1.3:1 as a reference.
The term “the thickness of substrate 41” refers to the thickness of cover 48 of blood sensor 24-5 shown in FIG. 9E, and the term “the thickness of cover 48” refers to the thickness of substrate 41 of blood sensor 24-5 shown in FIG. 9E.

[The Relationship Between the Volume of the Blood Storing Part and the Volume of the Blood Supply Channel]

As described above, blood sensor 24 has blood storing part 49 and blood supply channel 47 d, and the volume of blood storing part 49 is one to twenty times the volume of blood supply channel 47 d, preferably four to fifteen times, and, more preferably, five to seven times. For example, the volume of blood storing part 49 of blood sensor 24-1 shown in FIG. 9A may be 0.904 μL, and the volume of blood supply channel 47 d may be 0.144 μL. Further, the volume of blood storing part 49 of blood sensor 24-2 shown in FIG. 9B may be 0.766 μL, and the volume of blood supply channel 47 d may be approximately 0.144 μL. In this way, by controlling the volume ratio between blood storing part 49 and blood supply channel 47 d adequately, the speed of the blood flowing in the supply channel can be controlled to be constant and the flow rate of the blood flowing in the supply channel can be controlled adequately, so that the blood does not wash out reagent 50 and reacts with reagent 50 sufficiently, which realizes a correct test.
Further, by controlling the volume ratio between blood storing part 49 and blood supply channel 47 d, it is possible to reduce their volumes. Therefore, the amount of the blood sampled for a test can be reduced, and the load on the patient can be also reduced.

[The Relationship Between the Area of the Air Hole and the Area of the Puncturing Hole]

The diameter of air hole 48 c is preferably 50 to 500 μm (for example, 50 μm). If the diameter of air hole 48 c is made small, blood sampled excessively is less likely to flow out from air hole 48 c. Further, the area of air hole 48 c is preferably made smaller than the area of puncturing hole 48 e formed by blood collection needle 26. When the area of air hole 48 c is made larger than the area of puncturing hole 48 e, the resistance of puncturing hole 48 e against the flow of blood 23 becomes smaller than the resistance of air hole 48 c. Therefore, most of blood 13 sampled excessively flows out from puncturing hole 48 e, and the amount of blood 13 flowing out from air hole 48 c becomes extremely small. Accordingly, even if the blood is sampled excessively, reagent 50 is not washed out. That is, reagent 50 does not move from detecting section 40, and the components of blood 13 are examined correctly.
Further, preferably, the diameter of air hole 48 c is smaller than the diameter of blood collection needle 26 and approximately 10 to 80%, and, more preferably, approximately half.
Further, like blood sensor 24-4 shown in FIG. 9D, also in a case where hole 52 is formed in cover 48 in advance, the area of hole 52 is preferably larger than the area of air hole 48 c. Further, the area of hole 52 is preferably smaller than the area of hole 41 c formed in substrate 41.

[The Relationship of Water-Repellency and Hydrophilicity in the Parts of the Blood Sensor]

First, the reverse side of cover 48 (the surface pasted to the spacer) corresponding to “the inner surface of supply channel 47 d” is preferably subjected to hydrophilicity treatment to make the blood smoothly flow in supply channel 47 d by capillary action. Further, the reverse side of cover 48 corresponding to “the upper side of storing part 49” is preferably less hydrophilic than the reverse side of cover 48 corresponding to the inner surface of supply channel 47 d to make the blood more smoothly flow in supply channel 47 d.
The surface of cover 48 (the reverse side of the surface pasted to the spacer) is preferably subjected to water-repellency treatment to prevent the blood in storing part 49 from flowing out more than necessary from air hole 48 c or a hole of cover 48 (for example, puncturing hole 48 e by blood collection needle 26). Further, the reverse side of cover 48 corresponding to “the upper side of storing part 49” is preferably less water-repellent than the surface of cover 48 to prevent more effectively the blood in storing part 49 from flowing out.
In the surface of substrate 41 which abuts on the skin, at least the periphery of hole 41 c is preferably water-repellent, and the whole surface may be preferably refers to a state where the surface free energy is less than 43 mN/m. When the surface of substrate 41 which abuts on the skin is water-repellent, the blood sampled by puncturing the skin with blood collection needle 26 can be brought to storing part 49 more easily.
Further, in blood sensors 24-2 and 24-3 shown in FIG. 9B and FIG. 9C, the wall surface of hole 41 c and lifting part 41 d are preferably less hydrophilic than supply channel 47 d and less water-repellent than the surface of cover 48 (the reverse side of the surface pasted to the spacer).
The level of the hydrophilicity or water-repellency is adjusted by performing hydrophilicity treatment or water-repellency treatment.
To improve the hydrophilicity or water-repellency, it is only necessary to mix hydrophilic material or water-repellent material in the material of member constituting the blood sensor or apply hydrophilic material or water-repellent material to the surface of the member. By adjusting the amount of the hydrophilic material or water-repellent material to be mixed or applied, the level of hydrophilicity or water-repellency is also adjusted.
Further, by dissolving or removing hydrophilic material applied on the surface of hydrophobic material (plastic, for example, polyethylene terephthalate), the hydrophilicity can be reduced. Still further, the activity of the hydrophilic material can be adjusted by radiating UV.
Blood sensor 24 for which the hydrophilicity or the water-repellency is controlled as described above is manufactured with, for example, the following method. In advance, water-repellent treatment is applied to the upper surface of cover 48, and hydrophilic treatment is applied to the lower surface of cover 48. Further, in advance, the whole or the periphery of hole 41 c of the reverse side of substrate 41 (reverse side of the surface pasted to the spacer) may be subjected to hydrophobic treatment. Next, substrate 41, spacer 47 and cover 48 are stacked (spacer 47 is stacked on the surface of cover 48, where hydrophilicity treatment is applied).

[The Arrangement of Electrodes in the Blood Sensor]

FIG. 15 is a perspective plan view of blood sensor 24. Detection electrodes 42, 43, 44 and 45 are formed on substrate 41, and these detection electrodes 42 to 45 function as, for example, an active electrode, a sensing electrode, a counter electrode and an Hct electrode, in that order. The “active electrode” refers to an electrode for measuring blood components, the “sensing electrode” refers to an electrode for sensing whether or not the blood is supplied to the detecting section, the “counter electrode” refers to a counterpart electrode of the active electrode, and the “Hct electrode” refers to an electrode for measuring the hematocrit level in the blood. Detection electrodes 42 to 45 are connected to relevant connection electrodes 42 a, 43 a, 44 a and 45 a, respectively, and connection electrodes 42 a, 43 a, 44 a and 45 a are arranged along the outer periphery of substrate 41.
Detecting section 40 is included on substrate 41, and the reagent contacts with detecting section 40. Detecting section 40 preferably includes detection electrode 42 which functions as an active electrode and detection electrode 44 which functions as a counter electrode, and, on the other hand, preferably does not include detection electrode 45 which functions as an Hct electrode.
The blood flowing out from the skin punctured with blood collection needle 26 is brought to storing part 49. The blood brought to storing part 49 flows in supply channel 47 d by capillary action, is led by detecting section 40, and reacts with regent 50 in detecting section 40. The result of the reaction is led to connection electrodes 42 a, 43 a, 44 a and 45 a connected to the detection electrodes, respectively.
Further, the result of the reaction is led to terminals 33 a, 33 b, 33 c and 33 d formed at attaching part 21 a via connectors 27 a, 27 b, 27 c and 27 d which contact with connection electrodes 42 a, 43 a, 44 a and 45 a. And further, the result of the reaction is led to measuring circuit 32 from terminals 33 a to 33 d.
As shown in FIG. 15, connection electrodes 42 a to 45 a have contact parts 42 b to 45 b, respectively, to contact with the connectors. Contact parts 42 b, 43 b, 44 b and 45 b contact with connectors 27 a, 27 b, 27 c and 27 d, respectively. Contact parts 42 b, 43 b, 44 b and 45 b are preferably arranged around a specific point so as to surround the specific point and arranged at equiangular intervals centered on the specific point.
The “specific point” is preferably in storing part 49 (inside hole 41 c) on the surface of the substrate, and, more preferably, near the center of storing part 49. Further, the “specific point” may be on the surface of the substrate and on the axis where puncturing needle 26 moves. Still further, the specific point is preferably near the rotation center of the axis of the insertion direction for attaching the blood sampling cartridge to the attaching part, of the blood sampling cartridge.
Further, contact parts 42 b to 45 b are preferably arranged at approximately the same distance from the specific point.
In this way, connector 27 of the test apparatus contacts with blood sensor 24 at equiangular intervals centered on the specific point, so that the connector and the blood sensor can be connected adequately regardless of the angle at which the blood sampling cartridge is attached. Therefore, the blood sampling cartridge can be attached more readily.
As shown in FIG. 2 described above, by arranging each of connectors 27 a to 27 d between cross-shape convex parts 23 c or 23 d formed on the outer periphery of holder 23, the contact parts can be arranged at equiangular intervals centered on the barycentric point of the cross shape of the holder.
In case that contact parts 42 b, 43 b, 44 b and 45 b are arranged at equiangular intervals centered on the specific point, when blood sampling cartridge 22 is attached to attaching part 21 a and the contact parts contact with the connectors, each of the contact parts can contact with one of the connectors respectively even if the rotation angle with respect to the axis of the insertion direction of the blood sampling cartridge is arbitrary. On the other hand, it is not clear which connectors contact with which contact parts. Therefore, to insert readily the cartridge regardless of the rotation angle with respect to the axis of the insertion direction, a “reference electrode” is preferably provided for specifying which contact parts of the connection electrodes contact with which connectors.
FIG. 16 shows an example where blood sensor 24 has a reference electrode. Blood sensor 24 a shown in FIG. 16 has the “reference electrode” for specifying the positions of the connection electrodes in addition to connection electrodes 42 a to 45 a, as one of the connection electrodes. Blood sensor 24 a may be the same as blood sensor 24 shown in FIG. 15 except that the reference electrode is provided. The reference electrode shown in FIG. 16 is reference contact part 43 c, which is the position that contacts with the connector. Reference contact part 43 c is provided in connection electrode 43 a together with contact part 43 b, that is, contact part 43 b and reference contact part 43 c are connected via a conductor. Therefore, the resistance between contact part 43 b and reference contact part 43 c is zero. Reference contact part 43 c may be provided in one of connection electrodes 42 a to 45 a, and not always necessary provided in connection electrode 43 a.
Contact parts 42 b to 45 b and reference contact part 43 c are preferably provided near the outer periphery of blood sensor 24 a, arranged around the specific point and arranged at equiangular intervals centered on the specific point. Therefore, five connectors 27 of attaching part 21 a are provided at equiangular intervals centered on the specific point so as to correspond to contact parts 42 b to 45 b and reference contact part 43 c, respectively. The holder in this case does not have the cross shape shown in FIG. 2 and preferably has a star shape or the shape of a pentagon, and connectors 27 are provided around the star-shaped or pentagon-shaped holder at the same angle.
By providing reference contact part 43 c in addition to contact parts 42 a to 45 b, even if blood sampling cartridge 22 is inserted into attaching part 21 a at an arbitrary rotation angle with respect to the axis of the insertion direction, (A) one of the connectors can contact with one of the contact parts or the reference contact part, and (B) measuring circuit 32 can detect neighboring electrodes between which the electrical resistance is zero, specify connection electrodes including the reference contact part, specify the positions of connection electrodes 42 a to 45 a, and further specify the functions of the detection electrodes connected to the connection electrodes.
FIG. 17 shows another example where blood sensor 24 has a reference electrode. Connection electrodes 42 a to 45 a of blood sensor 24 b shown in FIG. 17 each have a contact part that contacts with a pair of two connectors. That is, connection electrode 42 a has contact parts 42 d and 42 e, connection electrode 43 a has contact parts 43 d and 43 e, connection electrode 44 a has contact parts 44 d and 44 e, and connection electrode 45 a has contact parts 45 d and 45 e. Only contact part 43 e out of contact parts 43 d and 43 e is formed on insulating member 53. Therefore, 43 d and 43 e are electrically insulated and the resistance between 43 d and 43 e becomes infinite, while the resistance between 42 d and 42 e, 44 d and 44 e, 45 d and 45 e becomes zero. To electrically insulate 43 d and 43 e, 43 d may be arranged on insulating member 53 provided on connection electrode 43 a, or 43 d and 43 e may be insulated by providing a slit around 43 d.
In this way, 43 e insulated from 43 d can be used as the reference contact part of the reference electrode. When the electrical resistance between the contact parts in pairs is measured, the resistance in one pair is infinite, so that it is possible to specify reference contact part 43 e. Using the specified reference contact position as a reference, the connection electrodes can be identified as connection electrode 43 a, connection electrode 44 a, connection electrode 45 a and connection electrode 42 a, clockwise, for example, and the functions of the detection electrodes connected to the connection electrodes can be specified.
Even if cartridge 22 to which the blood sensor (illustrated in FIG. 16 and FIG. 17) is attached, is inserted to attaching part 21 a of the blood test apparatus at an arbitrary rotation angle with respect to the axis of the insertion direction, connection electrodes 42 a to 45 a included in the blood sensor can be specified. Therefore, it is not necessary to adjust and correct the insertion direction of the cartridge by visual checking, so that the insertion becomes simple.
It is also possible to design blood sampling cartridge 22 so as not to be inserted unless the rotation angle with respect to the axis of the insertion direction is a specific angle, and make the specific connectors contact with the specific contact parts. For example, convex part 21 f and convex part 23 d of the guide shown in FIG. 6 do not have to be provided at regular intervals, but may be provided at different intervals.
Further, a groove (or a convex part) that runs from the front to the rear may be provided on the inner wall of attaching part 21 a, a convex part (or a groove) matching the groove (or the convex part) may be provided on the surface of the holder of blood sampling cartridge 22, and blood sampling cartridge 22 may be inserted by sliding in this groove (the convex part).
Further, it is also possible to provide a concave part (or a convex part) in holding part 30 a of plunger 30 and form a convex part (or a concave part) matching the concave part in grip part 25 f of lancet 25.

[The Principle of Measuring the Blood Sugar Level]

FIG. 18 shows the measurement principle of blood test apparatus 20 that measures the blood sugar level of blood. Glucose 101 in blood reacts with glucose dehydrogenase (GDH) 103 specifically to give product 102, and potassium ferricyanide 104 is reduced to generate potassium ferrocyanide 105.
The amount of generated potassium ferrocyanide 105 is proportional to the concentration of glucose 101. Potassium herrocyanide 105 is oxidized on detection electrode 42 (see FIG. 15) as an active electrode, and, at this time, oxidation response current 106 flowing toward detection electrode 44 as a counter electrode is proportional to the concentration of glucose 101. Therefore, the blood sugar level can be measured based on this oxidation response current 106.
FIG. 19 shows an output example of the measurement result of blood test apparatus 20. The horizontal axis shows the concentration (mg/dL) of glucose 101, and the vertical axis shows response current 106 (μA). In this way, oxidation response current 106 is proportional to the concentration of glucose 101.

[Test Process]

FIG. 20 shows the relationship between blood collection needle 26 and blood sensor 24 upon blood sampling by the blood test apparatus. As shown in FIG. 20A, substrate 41 of blood sensor 24 abuts on the skin of the patient (such as the skin of a finger). When blood collection needle 26 is shot in the direction of the arrow, blood collection needle 26 projects from blood sensor 24, and breaks through cover 48 in case that there is no opening part in cover 48 forming the upper side of storing part 49, and further, punctures skin 7. Blood 13 flows out from punctured skin 7, and the outflow of blood 13 is led to storing part 49. Blood 13 led to storing part 49 flows into supply channel 47 d, and, further, led to detecting section 40 by capillary action.
When the surface of substrate 41, that contacts with the skin, is subjected to water-repellency treatment, the blood flowing out from the skin can be led to storing part 49 efficiently.
Blood 13 is more likely to flow into supply channel 47 d, the inner surface of which is subjected to hydrophilicity treatment. When the inner surface of storing part 49 is less hydrophilic than the inner surface of supply channel 47 d, blood 13 is more likely to flow into supply channel 47 d. Further, when the upper surface of cover 48 is subjected to water-repellency treatment, the outflow of blood 13 from puncturing hole 52 a is minimized, so that blood 13 is more likely to flow into supply channel 47 d.
FIG. 20B shows the relationship between blood collection needle 26 and blood sensor 24 in which bank 51 is formed. As shown in FIG. 19, when sensor 24 is made to abut on skin 7 such as a finger of the patient and blood collection needle 26 is shot in the direction of the arrow, skin 7 is punctured and blood 13 flows out in the same way as in FIG. 20A. The outflow of blood 13 fills storing part 49.
At this time, bank 51 is formed near the opening, and so bank 51 is in close contact with skin 7. Therefore, blood 13 flowing out from skin 7 is more likely to be led to storing part and less likely to leak.
FIG. 21 shows cross-sectional views of blood sampling cartridge 22 and attaching part 21 a of blood test apparatus 20 into which blood sampling cartridge is inserted. As shown in FIG. 21, inside cylindrically-shaped attaching part 21 a, plunger 30 is provided slidably in the front-back direction (in the figure, in the horizontal direction). Holding part 30 a of plunger 30 holds grip part 25 f of lancet 25 included in blood sampling cartridge 22. Further, blood sampling cartridge 22 is held by elasticity of end 21 b of attaching part 21 a.
The position where blood sampling cartridge 22 is fixed at attaching part 21 a, is specified by a joint between positioning concave part 21 h provided in the cylinder of attaching part 21 a and positioning convex part 23 h provided in holder 23 forming blood sampling cartridge 22. By this means, blood sampling cartridge 22 is fixed at a specified position of attaching part 21 a. The contact parts (including the reference contact part) of blood sensor 24 contact with connectors 27, respectively. Terminals 33 are connected to connectors 27, respectively.
FIG. 21A shows a state where plunger 30 is pulled backward, and blood collection needle 26 is inside blood sampling cartridge 22. That is, FIG. 21A shows a state before puncturing.
FIG. 21B shows a state where plunger 30 projects forward. Blood collection needle 26 projects from blood sensor 24 (or blood sensor 24 a). In this state, blood is sampled by puncturing the patient's skin.
FIG. 21C shows a state where plunger 30 is pulled backward. Blood collection needle 26 is accommodated in blood sampling cartridge 22. Except for the state where plunger 30 projects forward, blood collection needle 26 is accommodated in blood sampling cartridge 22, so that blood collection needle 26 does not puncture the skin by error and is secure, and, further does not make the patient feel fear. Further, blood collection needle 26 does not allow direct touch, and so is secure.
FIG. 22 shows an example of the flow of the test using blood test apparatus 20. In step 61, blood sampling cartridge 22 is inserted into attaching part 21 a to be attached to blood test apparatus 20. By this insertion, holder 23 is pressed into attaching part 21 a and latched, and positioning concave part 21 h and positioning convex part 23 h are jointed to determine the position. Further, grip part 25 f of lancet 25 is held by holding part 30 a of plunger 30.
In step 62, blood sensor 24 of blood sampling cartridge 22 is pressed against the patient's skin and placed in close contact with the patient's skin. In step 63, a locking mechanism of plunger 30, formed by latch convex part 31 c provided in handle 31 and latch concave part 21 d provided in housing 21, is disengaged. In step 64, blood collection needle 26 attached to lancet 25 projects toward the skin by plunger 30 urged by the spring.
In step 65, after the patient's skin is punctured with blood collection needle 26, blood collection needle 26 is moved backward and accommodated in blood sampling cartridge 22. In step 66, blood flows out and is sampled. The outflow of blood is brought to blood sensor 24 and led to detecting section 40 placed inside supply channel 47 d. Then, after detection electrode 43 as a sensing electrode determines that blood of the amount necessary for measurement is led to the detecting section, sampling blood is finished. In this way, blood is not sampled more than necessary, so that it is possible to alleviate the load on the patient significantly.
In step 67, the glucose in the sampled blood is measured. After the glucose in the blood and a glucose oxidation-reduction enzyme are reacted for a certain period, a voltage is applied between detection electrode 42 as an active electrode and detection electrode 44 as a counter electrode. The mediator in a reduction condition, produced on detection electrode 42 by enzyme reaction, is oxidized, and its oxidation current is detected. The reaction time of a glucose and an oxidation-reduction enzyme is normally 10 seconds or less, the voltage applied in step 67 is normally 0.2 to 0.5 V, and the application time is normally 5 seconds or less. This application time is measured by timer 79 (described later).
In step 68, the hematocrit (Hct) level is measured. When a voltage is applied between detection electrode 45 as an active electrode and detection electrode 42 as a counter electrode, a current that depends on the Hct level is detected. The Hct level is measured based on the detected current. The measured Hct level is used to correct the result of measuring the glucose. The relationship between the current and the Hct level may be calculated in advance as a calibration curve, and the detected current may be applied as is.
Generally, the voltage applied in step 68 is approximately 2 to 3 V, and the application time is approximately 5 seconds or less. A mediator is not provided at detection electrode 45, which is an active electrode, there is a certain interval between detection electrode 45 and detection electrode 42, and only blood exists in this interval. Therefore, in step 68, an oxidation current that depends on the Hct level can be detected without being influenced by reagent 50.
Then, in step 69, the measurement result of the blood components is corrected. That is, using the Hct level measured in step 68, the glucose content calculated in step 67 is corrected. This correction is performed based on the calibration curve (including a calibration table) created in advance. The corrected glucose content is displayed on display section 75 of blood test apparatus 20.
After going through steps 67, 68 and 69 of blood sugar level measurement, used blood sampling cartridge 22 is collected or discarded every measurement.

[A Block Diagram of the Blood Test Apparatus]

FIG. 23 is a block diagram of blood test apparatus 20. The same components will be assigned the same reference numerals for ease of explanation. Blood test apparatus 20 in FIG. 23 has blood sensor 24 a shown in FIG. 16. Connection electrodes 42 a to 45 a of blood sensor 24 a are connected to terminals 33 a to 33 e. Terminals 33 a to 33 e are connected to switch circuit 71, and the output of switch circuit 71 is connected to the input of current/voltage converter 72. The output of current/voltage converter 72 is connected to the input of calculating section 74 via analogue/digital converter (hereinafter A/D converter) 73. The output of calculating section 74 is connected to display section (for example, a liquid crystal display device) and also connected to the input of transmitting section 77.
Further, reference voltage supply 78 is connected to switch circuit 71. Reference voltage supply 78 may be a ground potential. The output of controlling section 76 is connected to a control terminal of switch circuit 71, calculating section 74, transmitting section 77 and timer 79.
When a test is conducted using blood test apparatus 20 adopting blood sensor 24 a, it is necessary to specify which of terminals 33 a to 33 e connection electrodes 42 a to 45 a are connected to, before measuring the blood components. Therefore, by the command of controlling section 76, out of terminals 33 a to 33 e, terminals having conductivity with the neighboring terminals are specified. When a terminal having conductivity is specified, the electrode connected to the terminal is determined to be connection electrode 43 a. Based on the terminal connected to connection electrode 43 a as a reference, terminals connected to connection electrodes 44 a, 45 a and 42 a, are determined in that order.
In this way, after the terminals connected to connection electrodes 42 a to 45 a are determined, the blood components are measured. When blood sensor 24 (see FIG. 15) not having a reference electrode is used, terminals connected to connection electrodes 42 a to 45 a have already been determined, and so such a step is not necessary.
Next, switch circuit 71 is switched so that detection electrode 42 as an active electrode for measuring the amount of blood components is connected to current/voltage converter 72 via terminal 33. On the other hand, detection electrode 43 which serves as a sensing electrode for detecting the inflow of blood is connected to reference voltage supply 78 via terminal 33. A certain voltage is applied between detection electrode 42 and detection electrode 43. When the blood is led to the detecting section in this state, a current flows between detection electrode 42 and detection electrode 43. This current is converted to a voltage by current/voltage converter 72, and the voltage value is converted to a digital value by A/D converter 73. The digital value is outputted to calculating section 74. Calculating section 74 detects the inflow of blood based on the digital value.
Next, the amount of blood components (glucose) is measured. The glucose content is measured by, first, switching switch circuit 71 by the command of controlling section 76 so that detection electrode 42, which is an active electrode for measuring the glucose content, is connected to current/voltage converter 72 via terminal 33. On the other hand, detection electrode 44, which is a counter electrode for measuring the glucose content, is connected to reference voltage supply 78 via terminal 33.
While the glucose in blood and the oxidation-reduction enzyme are reacted for a certain period, current/voltage converter 72 and reference voltage supply 78 may be turned off. After the glucose in blood and the oxidation-reduction enzyme are reacted for a certain period (10 seconds or less), when a certain voltage (0.2 to 0.5 V) is applied between detection electrodes 42 and 44 by the command of controlling section 76, a current flows between detection electrode 42 and detection electrode 44. This current is converted to a voltage by current/voltage converter 72, and the voltage value is converted to a digital value by A/D converter 73 and outputted to calculating section 74. Calculating section 74 converts the digital value to a glucose content.
After the glucose content is measured, the Hct level is measured. First, by the command of controlling section 76, switch circuit 71 is switched to connect detection electrode 45, which is an active electrode for measuring the Hct level, to current/voltage converter via terminal 33. On the other hand, detection electrode 42, which is a counter electrode for measuring the Hct level, is connected to reference voltage supply 78.
Then, by the command of controlling section 76, a certain voltage (2 to 3 V) is applied between detection electrode 45 and detection electrode 42 from current/voltage converter 72 and reference voltage supply 78. The current flowing between detection electrode 45 and detection electrode 42 is converted to a voltage by current/voltage converter 72, and the voltage value is converted to a digital value by A/D converter 73 and outputted to calculating section 74. Calculating section 74 measures the Hct level based on the digital value.
From the measured Hct level and the glucose content, the glucose content is corrected with the Hct level with reference to the calibration curve or the calibration table. The result after correction may be displayed on display section 75 or transmitted to an injection apparatus that injects a curative drug (for example, insulin) from transmitting section 77. The result after correction may be transmitted by radio, but is preferably transmitted using optical communication which does not interfere with medical equipment.
In case that the injection apparatus for injecting curative drug can set a dose of the curative drug automatically based on the result after correction (measured data) transmitted from transmitting section 77, the patient does not have to set a dose of the curative drug, which eliminates the inconvenience of setting a dose. Further, the amount of insulin can be set for the injection apparatus without involving an artificial means, so that it is possible to prevent setting errors.

[The Negative Pressure Means]

The blood test apparatus of the present invention may have a negative pressure means. By the negative pressure means, a negative pressure is preferably applied near the part of the skin punctured with blood collection needle 26. Therefore, blood test apparatus 20 with the negative pressure means preferably has a member for surrounding the neighborhood of the punctured part of the skin, and may apply a negative pressure to the space surrounded by the member.
FIG. 24 is a block diagram of blood test apparatus 20-1 with a negative pressure means. Blood test apparatus 20-1 is different from blood test apparatus 20 shown in FIG. 23 in that blood test apparatus 20-1 has a negative pressure means, and so the difference will be mainly described. The same components as blood test apparatus 20 will be assigned the same reference numerals for ease of explanation.
In FIG. 24, guard member 81 is provided so as to extend from end 21 b of attaching part 21 a. Controlling section 76 a is connected to negative pressure section 82 (for example, a vacuum generator), and the output of negative pressure means 82 is connected inside of guard member 81 via negative pressure path 83. Therefore, negative pressure can be applied inside of guard member 81 by negative pressure means 82.
Negative pressure means 82 may be started up after step 62 in which blood sensor 24 a (which may be blood sensor 24) is made close contact with the measurement part, and stopped after step 66 in which blood is sampled. Upon sampling blood, by applying a negative pressure to the space between the skin punctured with the blood collection needle and blood sensor 24 a, the skin is put under a state of tension so as to enable fast and reliable blood sampling.
FIG. 25A shows a cross-sectional view of blood test apparatus 20-1. In FIG. 25A, guard member 81 is provided so as to extend from end 21 b of attaching part 21 a. The output of negative pressure means 82 (for example, a vacuum generator) connected to controlling section 76 a is connected inside guard member 81 via negative pressure path 83. Therefore, negative pressure means 82 can apply a negative pressure inside guard member 81.
FIG. 26 is a cross-sectional view that expands the main part near guard member 81 of blood test apparatus 20-1. In FIG. 25, as a result of the operation of negative pressure means 82, air pressure within inner part 81 a of guard member 81 is reduced as shown by arrow 83 a, and skin 7 is brought in close contact with sensor 24 of guard member 81 and put under a state of tension. At this time, air pressure within inner part 22 a of blood sampling cartridge 22 is also reduced.
Before puncturing with blood collection needle 26 (see FIG. 20), skin 7 is preferably plumped up by inspiring air in the inner part of storing part 49 in a direction of arrow 83 b through air hole 48 c so as to apply negative pressure to the inner part. By this means, skin 7 is put under a state of tension to make puncturing easier.
After puncturing with blood collection needle 26, air in the inner part of storing part 49 is inspired through puncturing hole 36 in addition to air hole 48 c as shown by arrow 83 c, and a negative pressure is further applied to further plumped skin 7 and help blood 13 to be sampled.
In this way, air hole 48 c and blood supply channel 47 d are also used as supply channels for negative pressure, so that it is possible to apply a negative pressure to the inner part of storing part 49 without providing a separate supply channel for negative pressure. Further, after puncturing, puncturing hole 52 a can be also used as a supply channel for negative pressure.
Guard member 81 in blood test apparatus 20-1 with the negative pressure means shown in FIG. 24, FIG. 25A and FIG. 26 may be used as second holder 38 shown in above-described FIG. 2B. When second holder 38 is used, the negative pressure means may apply a negative pressure to space formed by circular projecting part 38 a of second holder 38 and the skin.
FIG. 25B is a cross-sectional view showing a state where blood sampling cartridge 22-4 (the same also applies to a case of blood sampling cartridge 22-2) with second holder 38 is attached to housing 21 of blood test apparatus 20-2. How blood sampling cartridge 22-4 is attached to attaching part 21 a of housing 21 is shown in FIG. 8A to FIG. 8E. In FIG. 25B, negative pressure path 83 is formed in housing 21 and connected to the inside of blood sampling cartridge 22-4. By this means, it is possible to plump up the skin upon puncturing and sample blood fast after puncturing.
FIG. 27 shows a state where the patient tries to examine blood using blood test apparatus 20. The patient is trying to sample the blood from the index finger of the patient's left hand and measure blood components (for example, the blood sugar level). In blood test apparatus 20, attaching part 21 a is provided in one side of housing 21. Blood sampling cartridge 22 is inserted and fixed at attaching part 21 a, and blood sensor 24 is attached to one end of blood sampling cartridge 22. Further, display section 75 is provided in the other side of housing 21. As a mechanism for driving plunger 30, for example, the method disclosed in Japanese Patent Application Laid-Open No. 2006-314718 can be adopted. By this means, it is possible to realize a mechanism for preventing sticking twice and a mechanism for adjusting the depth of puncturing.
Further, blood test apparatus 20 may have a mechanism for adjusting the depth of puncturing, and, as an example of this mechanism, FIG. 27 shows puncturing depth adjusting control 84.
The blood test apparatus of the present invention can be used to measure a glucose, and also is suitable for measuring blood components such as the lactate level and cholesterol.

INDUSTRIAL APPLICABILITY

The blood test apparatus of the present invention can attach and remove a blood sampling cartridge including a blood collection needle and a blood sensor in a simple manner, and is applicable to medical equipment, and the like.
The disclosures of Japanese Patent Application No. 2006-000354, Japanese Patent Application No. 2006-000355, Japanese Patent Application No. 2006-000356, Japanese Patent Application No. 2006-000357 and Japanese Patent Application No. 2006-000358, filed on Jan. 5, 2006, and Japanese Patent Application No. 2006-022040, filed on Jan. 31, 2006, including the specifications, drawings and abstracts are incorporated herein by reference in its entirety.

Claims

1. A blood sampling cartridge that is attachable to and removable from an attaching part of a blood test apparatus having a housing, the attaching part being provided in one side of the housing, the blood sampling cartridge comprising:

a holder;

a blood sensor that is attachable to one end of the holder;

a lancet that is movable inside the holder;

a blood collection needle attached to one end of the lancet; and

a guide provided on the lancet,

wherein the guide of the lancet is configured to latch with the holder after puncturing with the blood collection needle, such that the blood collection needle is prevented from projecting beyond the blood sensor.

2. The blood sampling cartridge according to claim 1, wherein:

the holder has a hole,

the guide is provided on a side surface of the lancet, and

the guide is configured to latch with the hole of the holder.

3. The blood sampling cartridge according to claim 1, wherein:

the holder has a cylindrical shape, and has a plurality of holes in an outer surface of the holder,

the lancet has a rod shape,

the guide of the lancet comprises a plurality of guides provided on an outer surface of the lancet,

the plurality of guides are configured to latch with the plurality of holes, respectively.

4. The blood sampling cartridge according to claim 3, wherein the plurality of guides face each other.

5. The blood sampling cartridge according to claim 1, wherein:

the holder has a convex part,

the guide is provided on a side surface of the lancet, and

the guide is configured to latch with the convex part of the holder.

6. The blood sampling cartridge according to claim 1, wherein:

the blood collection needle is accommodated inside the holder above the blood sensor, and

the blood collection needle is configured to vertically pass through a surface of the blood sensor upon puncturing.

7. The blood sampling cartridge according to claim 1, wherein:

a front part of the holder of the blood sampling cartridge, with respect to an insertion direction of the attaching part, is thinner than a rear part of the holder.

8. The blood sampling cartridge according to claim 1, wherein:

the blood collection needle and the lancet of the blood sampling cartridge are integrated.

9. The blood sampling cartridge according to claim 1, wherein:

the blood sampling cartridge is dividable into the integrated blood collection needle and lancet, and the holder to which the blood sensor is attached.

10. The blood sampling cartridge according to claim 1, further comprising a second holder that covers a surface of the blood sensor, the surface facing outwardly from the holder,

wherein the second holder includes a circular concave part of 4 to 15 mm in diameter on the surface facing outwardly from the holder.

11. The blood sampling cartridge according to claim 1, further comprising a protective cap which covers the blood collection needle.

12. The blood sampling cartridge according to claim 10, further comprising a protective cap which covers the second holder.