DEVICE AND METHODS FOR CALIBRATING ANALYTE SENSORS

• US 20090018426A1
• Filed: 05/09/2008
• Published: 01/15/2009
• Est. Priority Date: 05/10/2007
• Status: Abandoned Application

• Current Assignee: Medtronic Minimed Incorporated (Medtronic Plc)
• Original Assignee: GluMetrics, Inc.
• Inventors: Markle, David R., Markle, William
• Application Number:
  US12/118,429
• Publication Number:
  US 20090018426A1
• Time in Patent Office: Days
• US Class Current: 600/365
• CPC Class Codes: A61B 5/14532 for measuring glucose, e.g. by tissue impedance measurement
• CPC Class Codes: A61B 5/1495 Calibrating or testing of in-vivo probes
• CPC Class Codes: G01N 27/3274 Corrective measures, e.g. error detection, compensation for temperature or hematocrit, calibration coding of calibration information G01N33/48771

Abstract

The present invention relates to methods and systems for multipoint calibration of an analyte sensor. More specifically, the methods can be used to calibrate glucose sensors.

Claims

1. A method of calibrating an analyte sensor, the method comprising:

providing a vessel containing a first solution, wherein a sensing region of the sensor is in contact with said first solution;

obtaining a first calibration signal from the sensor;

adding an amount of a second solution into said vessel by means of a syringe, whereupon said sensor produces another calibration signal; and

calculating a calibration factor using said first calibration signal and any additional calibration signals, thereby calibrating the analyte sensor.

2. The method according to claim 1, further comprising:

repeating the step of adding an amount of a second solution into said vessel by means of a syringe, whereupon said sensor produces another calibration signal.

3. The method according to claim 2, wherein the step of adding an amount of a second solution into said vessel by means of a syringe, whereupon said sensor produces another calibration signal, is repeated twice.

4. The method according to claim 1, wherein said syringe has at least one stop for adding a premeasured amount of the second solution.

5. The method according to claim 1, wherein said analyte sensor is a glucose sensor.

6. The method according to claim 5, wherein said glucose sensor is an intravascular glucose sensor.

7. The method according to claim 5, wherein said second solution is a glucose solution.

8. The method according to claim 7, wherein said glucose solution has a concentration of glucose between 0 mg/dL and 10 g/dL.

9. The method according to claim 1, wherein said analyte sensor is a pH sensor.

10. The method according to claim 9, wherein said second solution is an acid.

11. The method according to claim 9, wherein said second solution is a base.

12. The method according to claim 1, wherein said vessel is a tonometer.

13. A kit for multipoint calibration of an analyte sensor comprising:

a vessel containing a calibration solution, wherein said vessel has a port; and

a syringe for delivery of an analyte.

14. The kit according to claim 13, wherein said vessel is a tonometer.

15. A method of calibrating an analyte sensor, the method comprising:

providing a vessel comprising at least two linearly adjacent chambers, wherein each chamber contains a solution, and wherein each chamber is separated from the chamber adjacent to it by a divider such that the solution in each chamber is substantially prevented from mixing with the solution in any other chamber;

wherein a sensing region of the sensor is in contact with the solution in one of the chambers;

obtaining a first calibration signal from the sensor;

moving the sensing region of the sensor into an adjacent chamber, thereby contacting the sensing region with the solution in said adjacent chamber, whereupon the sensor produces an additional calibration signal; and

calculating a calibration factor using said first calibration signal and any additional calibration signals, thereby calibrating the analyte sensor.

16. The method according to claim 15, further comprising:

repeating the step of moving the sensing region of the sensor into an adjacent chamber, thereby contacting the sensing region with the solution in said adjacent chamber, whereupon the sensor produces a further additional calibration signal, until a calibration signal has been produced for each solution in each of the chambers.

17. The method according to claim 15, wherein said the step of moving the sensing region is carried out by retracting said sensor.

18. The method according to claim 15, wherein the step of moving the sensing region is carried out by advancing said sensor.

19. The method according to claim 15, wherein said sensor is a glucose sensor, and the solution in each chamber is a glucose solution.

20. The method according to claim 19, wherein said vessel comprises three linearly adjacent chambers:

a first chamber, a middle chamber, and a last chamber.

21. The method according to claim 20, wherein said glucose solution in each chamber has a different concentration of glucose.

22. The method according to claim 21, wherein the glucose concentration of the solution increases from the first chamber to the last chamber.

23. The method according to claim 22, wherein the glucose concentration of the solution in the first chamber is 0 mg/dL, the glucose concentration of the solution in the middle chamber is 100 mg/dL, and glucose concentration of the solution in the last chamber is 400 mg/dL.

24. A method of calibrating an analyte sensor, the method comprising:

exposing the sensing region of the sensor to a solution, whereupon the sensor produces a first calibration signal;

combining at least one timed-release capsule with said solution, wherein said timed-release capsule contains an analyte;

allowing each timed-release capsule to release said analyte contained within it, whereupon the sensor produces another calibration signal; and

calculating a calibration factor using said first calibration signal and any additional calibration signals, thereby calibrating said analyte sensor.

25. The method according to claim 24, wherein said timed-release capsule takes between 10 seconds and 60 minutes to release said analyte contained within it.

26. The method according to claim 24, wherein said timed-release capsule comprises a degradable membrane.

27. The method according to claim 25, wherein said degradable membrane has a dissolution rate proportional to the thickness of said degradable membrane.

28. The method according to claim 24, wherein said method comprises combining three timed-release capsules with said solution.

29. The method according to claim 24, wherein said analyte sensor is a glucose sensor.

30. The method according to claim 29, wherein said analyte is glucose.

31. The method according to claim 30, wherein said glucose is in solution.

32. The method according to claim 30, wherein said glucose is not in solution.

33. The method according to claim 31, wherein said glucose has a concentration of between 0 mg/dL and 10 g/dL.

34. A method of calibrating an analyte sensor, the method comprising:

obtaining a vessel containing a solution, wherein a sensing region of the sensor is in contact with said solution; and

wherein said vessel comprises at least one rupturable chamber containing an analyte, wherein said analyte is initially substantially separated from said solution;

obtaining a first calibration signal from the sensor;

rupturing each rupturable chamber, thereby releasing the analyte within it, whereupon the sensor produces another calibration signal; and

calculating a calibration factor using said first calibration signal and any additional calibration signals, thereby calibrating said analyte sensor.

35. The method according to claim 34, wherein said vessel comprises two rupturable chambers.

36. The method according to claim 34, wherein said analyte sensor is a glucose sensor.

37. The method according to claim 34, wherein said analyte is a glucose solution.

38. The method according to claim 37, wherein said glucose solution has a concentration of glucose between 0 mg/dL and 10 g/dL.

39. The method according to claim 34, wherein said rupturable chamber is rotatable, and wherein said rupturable chamber is ruptured by rotating said rupturable chamber, thereby releasing said analyte.

40. The method according to claim 39, wherein said rupturable chamber is ruptured by shearing when said rupturable chamber is rotated.

41. The method according to claim 39, wherein said rupturable chamber comprises a valve, wherein said valve remains in a closed position until said rupturable chamber is rotated, whereupon said valve opens, thereby releasing said analyte.

42. The method according to claim 34, wherein said rupturable chamber is ruptured by exerting pressure on said rupturable chamber, thereby rupturing said chamber and releasing said analyte.

43. A ready-to-calibrate and deploy, sterilized analyte sensor kit, comprising:

an analyte sensor comprising an elongate body having an indicator system disposed along a distal portion of the elongate body; and

a calibration vessel comprising a sensor port through which the distal portion of the sensor is sealably retained within the vessel until retracted for use, and the vessel further comprising a calibration means in fluid communication with the vessel,

wherein the sensor and vessel are pre-assembled, sterilized and sealed within a sterile package, ready for calibration and deployment.

44. The kit of claim 43, wherein the calibration means comprises a calibration port in fluid communication with the vessel and a syringe comprising a calibration solution fluidly-coupled to the vessel via the calibration port.

45. A ready-to-calibrate and deploy, sterilized analyte sensor kit, comprising:

an analyte sensor comprising an elongate body having an indicator system disposed along a distal portion of the elongate body and an coupling member configured to interface with an analyte monitor comprising a calibration algorithm;

a calibration apparatus comprising a calibration chamber sized to slidably receive and accommodate therein the distal portion of the elongate body of the sensor, an adjustable sealing means for sealing the distal portion within the calibration chamber, an infusion port fluidly coupled to the calibration chamber, and a fluid waste receptacle fluidly coupled to the calibration chamber; and

wherein the analyte sensor is slidably engaged within the calibration apparatus, sterilized and sealed within a sterile package, ready for calibration and deployment.

46. The kit of claim 45, further comprising a heater configured to heat the calibration chamber and a temperature sensor configured to measure the temperature within the calibration chamber.

47. A method of calibrating an analyte sensor, the method comprising:

providing the analyte sensor kit of claim 45;

providing at least first and second calibration solutions in separate syringes;

providing the analyte monitor;

coupling the analyte sensor to the analyte monitor via the coupling member;

initiating the calibration algorithm;

infusing the first calibration solution into the calibration chamber;

allowing the sensor to equilibrate;

infusing the second calibration solution into the calibration chamber, collecting displaced fluid in the waste receptacle; and

allowing the sensor to equilibrate, wherein the calibration algorithm automatically calibrates the sensor.

48. The method according to claim 47, further comprising:

providing a heater configured to heat the calibration chamber and a temperature sensor configured to measure the temperature within the calibration chamber;

heating the first calibration solution to a target temperature; and

heating the second calibration solution to the target temperature.