Small volume in vitro analyte sensor with diffusible or non-leachable redox mediator

• US 6,591,125 B1
• Filed: 06/27/2000
• Issued: 07/08/2003
• Est. Priority Date: 06/27/2000
• Status: Expired due to Term

• Current Assignee: Abbott Diabetes Care Incorporated (Abbott Laboratories Incorporated)
• Original Assignee: Therasense Incorporated (Abbott Laboratories Incorporated)
• Inventors: Moses, Alan Charles, Buse, John Bernard
• Primary Examiner(s): Nasser, Robert L.
• Assistant Examiner(s): MALLARI, PATRICIA C
• Application Number:
  US09/604,614
• Time in Patent Office: 1,106 Days
• Field of Search: 600/300-301, 600/345, 600/347, 600/365, 600/573, 436/95, 436/180, 436/174, 436/183
• US Class Current: 600/347
• CPC Class Codes: A61B 2562/0295 Strip shaped analyte sensors for apparatus classified in A61B5/145 or A61B5/157 disposable multilayered or laminated electrodes G01N27/307; details of handling chemical test elements G01N33/4875
• CPC Class Codes: A61B 5/1411 by percutaneous method, e.g. by lancet
• CPC Class Codes: A61B 5/14532 for measuring glucose, e.g. by tissue impedance measurement
• CPC Class Codes: A61B 5/14546 for measuring analytes not otherwise provided for, e.g. ions, cytochromes
• CPC Class Codes: A61B 5/1468 using chemical or electrochemical methods, e.g. by polarographic means A61B5/1486 takes precedence
• CPC Class Codes: A61B 5/150022 for capillary blood or interstitial fluid
• CPC Class Codes: A61B 5/150358 Strips for collecting blood, e.g. absorbent optical reagent test strips G01N21/8483; chemical reagent test strips G01N33/4875, G01N33/52
• CPC Class Codes: A61B 5/150412 Pointed piercing elements, e.g. needles, lancets for piercing the skin blade-like piercing elements A61B5/150442
• CPC Class Codes: A61B 5/150442 Blade-like piercing elements, e.g. blades, cutters, knives, for cutting the skin
• CPC Class Codes: A61B 5/150503 Single-ended needles hollow piercing element tip design A61B5/150396, needle sets for catheters A61M25/06, needles for bringing media into the body A61M5/32
• CPC Class Codes: A61B 5/15144 comprising driving means, e.g. a spring, for retracting the piercing unit into the housing
• CPC Class Codes: A61B 5/15194 fully automatically retracted, i.e. the retraction does not require a deliberate action by the user, e.g. by terminating the contact with the patient's skin
• 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: G01N 33/48707 by electrical means G01N33/49, G01N33/493 take precedence
• CPC Class Codes: G01N 33/49 Blood chemical methods for determining blood cell populations G01N33/5094; chemical analysis of blood groups or blood types G01N33/80
• CPC Class Codes: G01N 33/66 involving blood sugars, e.g. galactose

Abstract

A region of skin, other than the fingertips, is stimulated. After stimulation, an opening is created in the skin (e.g., by lancing the skin) to cause a flow of body fluid from the region. At least a portion of this body fluid is transported to a testing device where the concentration of analyte (e.g., glucose) in the body fluid is then determined. It is found that the stimulation of the skin provides results that are generally closer to the results of measurements from the fingertips, the traditional site for obtaining body fluid for analyte testing.

Claims

1. A method of determining a concentration of glucose in blood, the method comprising steps of:

stimulating a region of forearm skin by manually rubbing the forearm skin for a period of time adequate to obtain a glucose measurement that is at least 10% nearer a concentration determined from blood obtained from a fingertip measurement than a determination of the concentration of glucose from blood obtained from the region of skin without stimulating;

after stimulating the region of the forearm skin, lancing the forearm skin to cause a flow of blood from the region;

coupling an electrochemical sensor strip to a meter;

contacting the sensor strip to the blood and tran sporting no more than about 1 microliter of the blood to a sample chamber in the sensor strip; and

electrochemically determining the concentration of glucose using coulometry, amperometry or potentiometry.

2. The method of claim 1, wherein the step of stimulating the region of forearm skin comprises manually rubbing the forearm skin for a period of at least one second.

3. The method of claim 1, wherein the step of stimulating the region of forearm skin comprises manually rubbing the forearm skin for a period of at least 2 seconds.

4. The method of claim 1, wherein the step of stimulating the region of forearm skin comprises manually rubbing the forearm skin for a period of at least 5 seconds.

5. The method of claim 1, wherein the step of transporting no more than about 1 microliter of the blood to a sample chamber in the sensor strip comprises transporting no more than about 0.5 microliter of the blood.

6. The method of claim 5, wherein the step of transporting no more than about 0.5 microliter of the blood comprises transporting no more than about 0.25 microliter of the blood.

7. The method of claim 6, wherein the step of transporting no more than about 0.25 microliter of the blood comprises transporting no more than about 0.1 microliter of the blood.

8. The method of claim 1, wherein the step of coupling an electrochemical sensor strip comprises coupling a tip-fill electrochemical sensor strip.

9. The method of claim 1, wherein the step of coupling an electrochemical sensor strip comprises coupling a side-fill electrochemical sensor strip.

10. The method of claim 1, wherein the step of electrochemically determining the concentration of glucose comprises determining the concentration of glucose using coulometry.

11. The method of claim 1, wherein the step of electrochemically determining the concentration of glucose comprises determining the concentration of glucose using amperometry.

12. The method of claim 1, wherein the step of electrochemically determining the concentration of glucose comprises determining the concentration of glucose using potentiometry.

13. The method of claim 1 wherein the fingertip measurement is in the range of 60 to 80 mg/dL.

14. A method of determining a concentration of glucose in blood, the method comprising the steps of:

manually rubbing a region of forearm skin for a period of time adequate to obtain a glucose measurement that is at least 10% nearer a concentration determined from blood obtained from a fingertip measurement than a determination of the concentration of glucose from blood obtained from the region of forearm skin without stimulating;

after rubbing the region of the forearm skin, lancing the region rubbed to cause a flow of blood from the region;

coupling an electrochemical sensor strip to a meter;

contacting the sensor strip with the blood and drawing the blood into a measurement zone within a sample chamber in the strip, the measurement zone being sized to contain no more than about 1 microliter of the blood; and

electrochemically determining the concentration of glucose using amperometry.

15. The method of claim 14 wherein the fingertip measurement is in the range of 60 to 80 mg/dL.

16. The method of claim 14 wherein the step of contacting comprises contacting an end edge of an end-fill sensor strip with the blood.

17. The method of claim 16 wherein the fingertip measurement is in the range of 60 to 80 mg/dL.

18. A method of determining a concentration of glucose in blood, the method comprising the steps of:

stimulating a region of forearm skin by manually rubbing the skin for at least 1 second;

after stimulating the region of the forearm skin, lancing the forearm skin to cause a flow of blood from the region;

coupling a side-fill electrochemical sensor strip to a meter;

contacting a side edge of the sensor strip to the blood and transporting no more than about 1 microliter of the blood to a sample chamber in the sensor strip; and

electrochemically determining the concentration of glucose using coulometry, amperometry or potentiometry.

19. The method of claim 18, wherein the step of stimulating the region of forearm skin comprises manually rubbing the region of forearm skin for at least two seconds.

20. The method of claim 18, wherein the step of electrochemically determining the concentration of glucose comprises determining the concentration of glucose using potentiometry.

21. The method of claim 18, wherein the step of lancing the forearm skin comprises creating an opening in the region of skin to cause a flow of no more than 5 □

L of blood.

22. The method of claim 18, wherein the step of transporting no more than about 1 microliter of the blood comprises transporting no more than about 0.5 microliter of the blood.

23. The method of claim 22, wherein the step of transporting no more than about 0.5 microliter of the blood comprises transporting no more than about 0.25 microliter of the blood.

24. The method of claim 23, wherein the step of transporting no more than about 0.25 microliter of the blood comprises transporting no more than about 0.1 microliter of the blood.

25. The method of claim 18, wherein the step of stimulating the region of forearm comprises manually rubbing the region of forearm skin for at least five seconds.

26. The method of claim 18, wherein the step of coupling an electrochemical sensor strip to a meter comprises coupling an electrochemical sensor strip comprising facing electrode pairs.

27. The method of claim 18, wherein the step of electrochemically determining the concentration of glucose comprises determining the concentration of glucose using coulometry.

28. The method of claim 18, wherein the step of electrochemically determining the concentration of glucose comprises determining the concentration of glucose using amperometry.

29. A method of determining a concentration of glucose in blood, the method comprising the steps of:

manually rubbing a region of forearm skin for at least 1 second;

after rubbing the region of the forearm skin, lancing the region rubbed to cause a flow of blood from the region;

coupling a side-fill electrochemical sensor strip comprising a working electrode and a counter electrode to a meter;

contacting a side edge of the sensor strip to the blood and drawing the blood into a sample chamber in the test strip and a measurement zone within the sample chamber between the two electrodes, the measurement zone being sized to contain no more than about 1 microliter of the blood; and

electrochemically determining the concentration of glucose using coulometry, amperometry or potentiometry.

30. The method of claim 29, wherein the step of electrochemically determining the concentration of glucose comprises determining the concentration of glucose using coulometry.

31. The method of claim 29, wherein the step of electrochemically determining the concentration of glucose comprises determining the concentration of glucose using amperometry.

32. The method of claim 29, wherein the step of electrochemically determining the concentration of glucose comprises determining the concentration of glucose using potentiometry.

33. The method of claim 29, wherein the step of coupling an electrochemical sensor strip comprises coupling an electrochemical sensor strip having a measurement zone being sized to contains no more than about 0.5 microliter of the blood.

34. The method of claim 33, wherein the step of coupling an electrochemical sensor strip comprises coupling an electrochemical sensor strip having a measurement zone being sized to contain no more than about 0.25 microliter of the blood.

35. The method of claim 34, wherein the step of coupling an electrochemical sensor strip comprises coupling an electrochemical sensor strip having a measurement zone being sized to contain no more than about 0.1 microliter of the blood.

36. The method of claim 29, wherein the step of manually rubbing the region of forearm skin comprises manually rubbing the region of forearm skin for at least two seconds.

37. The method of claim 36, wherein the step of manually rubbing the region of forearm skin comprises manually rubbing the region of forearm skin for at least five seconds.