Systems and methods for blood glucose sensing

• US 7,819,161 B2
• Filed: 11/01/2006
• Issued: 10/26/2010
• Est. Priority Date: 04/25/2002
• Status: Expired due to Fees

• Current Assignee: Trividia Health, Inc. (Sinocare, Inc.)
• Original Assignee: Nipro Diagnostics, Inc.
• Inventors: Wong, T. Philip, Voss, Houston F., Boehm, David K., Caban, Allan Javier, Neel, Gary T., Bell, Douglas E.
• Primary Examiner(s): Olsen; Kaj K
• Application Number:
  US11/590,854
• Publication Number:
  US 20070089987A1
• Time in Patent Office: 1,455 Days
• Field of Search: 204/403.01, 204/403.02, 204/403.04, 205/777.5, 205/792, 156/510
• US Class Current: 156/510
• CPC Class Codes: C12Q 1/006 for glucose
• CPC Class Codes: G01N 27/3272 Test elements therefor, i.e. disposable laminated substrates with electrodes, reagent and channels optical biosensors G01N33/52
• CPC Class Codes: Y10T 156/12 Surface bonding means and/or assembly means with cutting, punching, piercing, severing or tearing
• CPC Class Codes: Y10T 29/49002 Electrical device making
• CPC Class Codes: Y10T 436/104998 Glucose, ketone, nitrate standard or control
• CPC Class Codes: Y10T 436/144444 Glucose

Abstract

A system for measuring a glucose level in a blood sample includes a test strip and a meter. The test strip includes a sample chamber, a working electrode, a counter electrode, fill-detect electrodes, and an auto-on conductor. A reagent layer is disposed in the sample chamber. The auto-on conductor causes the meter to wake up and perform a test strip sequence when the test strip is inserted in the meter. The meter uses the working and counter electrodes to initially detect the blood sample in the sample chamber and uses the fill-detect electrodes to check that the blood sample has mixed with the reagent layer. The meter applies an assay voltage between the working and counter electrodes and measures the resulting current. The meter calculates the glucose level based on the measured current and calibration data saved in memory from a removable data storage device associated with the test strip.

Claims

1. A method for making a plurality of test strips, comprising:

forming an array of test strip structures on a first insulating sheet, each of the test strip structures including;

a first conductive pattern disposed on the first insulating sheet, the first conductive pattern forming at least four electrodes including a working electrode, a counter electrode, a fill-detect cathode, and a fill-detect anode,

a second conductive pattern disposed on the first insulating sheet spaced from the first conductive pattern, the second conductive pattern including a plurality of spaced electrical contacts, and

a plurality of conductive traces disposed on the first insulating sheet for electrically connecting the first and second conductive patterns,

attaching a second insulating sheet to the first insulating sheet, the second insulating sheet formed to include a slot defining a sample chamber in the test strip, the slot including a proximal end and a distal end;

attaching a cover layer to the second insulating sheet with an adhesive layer, the adhesive layer including the break, the break extending from the distal end of the slot to an opening for venting the sample chamber, and the cover layer overlying the slot and the break; and

separating the plurality of test strip structures into the plurality of test strips.

2. The method of claim 1, wherein the cover layer is transparent.

3. The method of claim 1, wherein the plurality of spaced electrical contacts are at least partially exposed nearest to a distal end of each of the test strip structures.

4. The method of claim 1, wherein the plurality of spaced electrical contacts include a working electrode contact, a counter electrode contact, a fill-detect cathode contact, and a fill-detect anode contact.

5. The method of claim 1, wherein the slot is disposed nearest to a proximal end of each of the test strip structures.

6. The method of claim 5, wherein the slot defining the sample chamber at least partially exposes the at least four electrodes.

7. The method of claim 1, wherein the plurality of conductive traces include a working electrode trace, a counter electrode trace, a fill-detect cathode trace, and a fill-detect anode trace.

8. The method of claim 7, wherein the working electrode trace electrically connects the working electrode to the working electrode contact.

9. The method of claim 7, wherein the counter electrode trace electrically connects the counter electrode to the counter electrode contact.

10. The method of claim 7, wherein the fill-detect cathode trace electrically connects the fill-detect cathode to the fill-detect cathode contact.

11. The method of claim 7, wherein the fill-detect anode trace electrically connects the fill-detect anode to the fill-detect anode contact.

12. The method of claim 1, wherein the first conductive pattern is disposed nearest to a proximal end of each of the test strip structures.

13. The method of claim 1, wherein the working electrode and the counter electrode are disposed in an interleaving manner nearest to a proximal end of each of the test strip structures.

14. The method of claim 1, wherein the plurality of test strips are separated by punching each of the test strip structures to form a plurality of tapered structures.

15. The method of claim 14, wherein the plurality of test strips are further separated by slitting the plurality of tapered test strip structures into the plurality of test strips.

16. A method for making a plurality of test strips, comprising:

forming an integrated laminated structure including an array of test strip structures, the plurality of test strip structures including;

at least four electrodes disposed on a base layer in the integrated structure, the electrodes including a working electrode, a counter electrode, a fill-detect cathode, and a fill-detect anode,

a plurality of electrical contacts disposed in spaced relation from the electrodes on the base layer,

a plurality of conductive traces disposed on the base layer for electrically connecting the at least four electrodes and the plurality of electrical contacts,

a spacer layer attached to the base layer, the spacer layer including a slot defining a sample chamber in the test strip, the slot including a proximal end and a distal end, and

a cover layer attached to the spacer layer with an adhesive layer, the adhesive layer including a break, the break extending from the distal end of the slot to an opening for venting the sample chamber, and the cover layer overlying the slot and the break, and

separating the plurality of test strip structures on the integrated structure into the plurality of test strips.

17. The method of claim 16, wherein the plurality of electrical contacts include a working electrode contact, a counter electrode contact, a fill-detect cathode contact, and a fill-detect anode contact.

18. The method of claim 17, wherein the plurality of electrical contacts are disposed nearest to a distal end of each of the test strip structures.

19. The method of claim 16, wherein the plurality of conductive traces include a working electrode trace, a counter electrode trace, a fill-detect cathode trace, and a fill-detect anode trace.

20. The method of claim 19, wherein the plurality of conductive traces are longitudinally disposed on each of the test strip structures.

21. The method of claim 16, wherein the at least four electrodes are disposed nearest to a proximal end of each of the test strip structures.

22. The method of claim 16, wherein the cover layer is transparent.

23. The method of claim 16, wherein the slot is disposed nearest to a proximal end of each of the test strip structures.

24. The method of claim 23, wherein the slot defining the sample chamber at least partially exposes the at least four electrodes.

25. The method of claim 16, wherein the plurality of test strips are separated by punching the test strip structures to form a plurality of tapered structures.

26. The method of claim 25, wherein the plurality of test strips are further separated by slitting the plurality of tapered test strip structures into the plurality of test strips.

27. A method for making a plurality of test strips, comprising:

forming an array of test strip structures on a first substrate having a first edge and a second edge, the plurality of test strip structures including;

a plurality of electrodes sequentially disposed on the first substrate on a first region relatively nearest to the first edge for each test strip structure, the plurality of electrodes including at least a working electrode, a counter electrode, a fill-detect cathode, and a fill-detect anode,

a plurality of electrical contacts disposed on the first substrate on a second region relatively nearest to the second edge for each test strip structure, and

a plurality of conductive traces on the first substrate electrically connecting the plurality of electrodes and the plurality of electrical contacts,

attaching a second substrate to the first substrate, the second substrate having a slot defining a sample chamber in each test strip structure, the slot including a proximal end and a distal end, and the second substrate having a third edge and a fourth edge aligned, respectively, with the first edge and the second edge of the first substrate, the fourth edge being spaced from the second edge to at least partially expose the second region for each test strip structure;

attaching a cover layer to the second substrate with an adhesive layer, the adhesive layer including a break, the break extending from the distal end of the slot to an opening for venting the sample chamber, the cover layer overlying the slot and the break for each test strip structure, and the cover layer having a fifth edge and a sixth edge, the sixth edge being spaced from the fourth edge of the second substrate; and

separating the plurality of test strip structures into the plurality of test strips by punching the test strip structures to form a plurality of tapered structures, and slitting the plurality of tapered test strip structures into the plurality of test strips.

28. The method of claim 27, wherein the plurality of electrical contacts include a working electrode contact, a counter electrode contact, a fill-detect cathode contact, and a fill-detect anode contact.

29. The method of claim 27, wherein the plurality of conductive traces include a working electrode trace, a counter electrode trace, a fill-detect cathode trace, and a fill-detect anode trace.

30. The method of claim 27, wherein the second substrate includes a

slot defining a sample chamber in the test strip.

31. The method of claim 30, wherein the slot is disposed nearest to the third edge of each of the test strip structures.

32. The method of claim 31, wherein the slot defining the sample chamber at least partially exposes the plurality of electrodes.

33. The method of claim 27, wherein the cover layer is transparent.

34. The method of claim 27, wherein the plurality of electrical contacts are at least partially exposed nearest to the second edge of each of the test strip structures.

35. The method of claim 27, wherein the working electrode and the counter electrode are disposed in an interleaving manner nearest to the first edge of each of the test strip structures.