METHODS OF USING AN ELECTROCHEMICAL BIOSENSOR

• US 20130161206A1
• Filed: 02/25/2013
• Published: 06/27/2013
• Est. Priority Date: 02/06/2004
• Status: Active Grant

• Current Assignee: Ascensia Diabetes Care Holdings AG (PHC Holdings Corporation)
• Original Assignee: Bayer Healthcare LLC (Bayer AG)
• Inventors: Huang, Dijia, Charlton, Steven C., George, Suny J., Edelbrock, Andrew J.
• Granted Patent: US 8,702,961 B2
• Time in Patent Office: Days
• US Class Current: 205/792
• 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 27/3274 Corrective measures, e.g. error detection, compensation for temperature or hematocrit, calibration coding of calibration information G01N33/48771
• CPC Class Codes: G01N 27/3275 Sensing specific biomolecules, e.g. nucleic acid strands, based on an electrode surface reaction
• CPC Class Codes: G01N 27/4163 checking the operation of, or calibrating, the measuring apparatus G01N27/3274, G01N27/4175 and G01N33/0006 take precedence
• CPC Class Codes: Y10T 29/49082 Resistor making
• CPC Class Codes: Y10T 29/49099 Coating resistive material on a base

Abstract

According to one embodiment of the present invention, an electrochemical sensor (10) for detecting the concentration of analyte in a fluid test sample is disclosed. The sensor (10) includes a counter electrode having a high-resistance portion for use in detecting whether a predetermined amount of sample has been received by the test sensor.

Claims

1-35. -35. (canceled)

36. A method for evaluating whether an electrochemical sensor is properly filled, comprising:

introducing the fluid test sample to the electrochemical test sensor;

applying a first potential between a counter electrode and a working electrode for a first predetermined time period after the fluid test sample has electrically connected the working electrode and the counter electrode;

after the first predetermined time period, applying a second potential between the counter electrode and the working electrode for a second predetermined time period, the second potential having a magnitude that is greater than a magnitude of the first potential;

measuring the current between the counter electrode and the working electrode at a first interval during the first predetermined time period to obtain a first current measurement;

measuring the current between the counter electrode and the working electrode at a second interval during the second predetermined period to obtain a second current measurement;

determining a first parameter based on the first current measurement and the second current measurement;

comparing the first parameter to at least one first predetermined parameter; and

notifying a user that an insufficient quantity of fluid test sample has been introduced to the electrochemical test sensor based on the comparing the first parameter to the at least one first predetermined parameter.

37. The method of claim 36, wherein the first parameter is determinable by a calculation having the general form

first parameter=ln(I_t1)−

ln(I_t2)/(ln(t2)−

ln(t1))

where I_t1 is the first current measurement at the first interval, t1, and I_t2 is the second current measurement at the second interval, t2.

38. The method of claim 36, wherein the second current measurement has a magnitude that is greater than a magnitude of the first current measurement when an insufficient quantity of fluid test sample has been introduced to the electrochemical test sensor.

39. The method of claim 36, further comprising:

after the second time period, applying a third potential between the counter electrode and the working electrode for a third predetermined time period;

measuring the current between the counter electrode and the working electrode at a third interval during the third predetermined time period to obtain a third current measurement;

measuring the current between the counter electrode and the working electrode at a fourth interval during the third predetermined time period to obtain a fourth current measurement;

determining a second parameter based on the third current measurement and the fourth current measurement;

comparing a second parameter to at least one second predetermined parameter; and

notifying a user that an insufficient quantity of fluid test sample has been introduced to the electrochemical test sensor based on the comparing the second parameter to the at least one second predetermined parameter.

40. The method of claim 39, wherein the second parameter is determinable by a Calculation having the general form

second parameter=ln(I₃)−

ln(I_t4)/(ln(t4)−

ln(t3))

where I_t3 is the third current measurement at the third interval, t3, and I_t4 is the fourth current measurement at the fourth interval, t4.

41. The method of claim 39, wherein the applying the third potential is in response to a determination that an insufficient quantity of fluid has been introduced to the electrochemical test sensor based on the comparing the first parameter to the at least one first predetermined parameter.

42. The method of claim 39, wherein the first predetermined time period and the second predetermined time period comprise a burn period, the third predetermined time period comprises a read period, and no potential is applied between the counter electrode and the working electrode for a wait period, the wait period being after the burn period and prior to the read period.

43. The method of claim 42, wherein the first potential is applied for about 25% to about 75% of the burn period.

44. The method of claim 39, wherein the first predetermined time period and the second predetermined time period comprise a first pulse period, and the third predetermined time period comprises a second pulse period.

45. The method of claim 39, wherein the second parameter is indicative of whether a current profile has a decay-type shape in response to the applying of the third potential.

46. A method for evaluating whether an electrochemical sensor is properly filled, the test sensor including a working electrode coupled to a first lead, and counter electrode coupled to a second lead, the method comprising:

collecting a blood sample;

applying a first potential across the first and second leads for a first predetermined time period;

after the first predetermined time period, applying a second potential across the first and second leads for a second predetermined time period, the second potential having a magnitude that is greater than a magnitude of the first potential; and

measuring the current at the first and second leads at at least one interval in response to the applied first potential and the applied second potential.

47. The method of claim 46, further comprising generating an under-filled error signal based on the measured current at the at least one interval.

48. The method of claim 46, wherein the at least one interval comprises at least a first interval and a second interval and the method further comprises determining whether the electrochemical sensor is properly filled based on the current measured at the first interval and the current measured at the second interval.

49. The method of claim 48, wherein the determining whether the electrochemical sensor is properly filled comprises determining a parameter based on the current measured at the first interval and the current measured at the second interval and comparing the parameter to a predetermined parameter.

50. The method of claim 46, wherein the at least one interval includes the first predetermined time period and the second predetermined time period.

51. The method of claim 50, further comprising determining whether the electrochemical sensor is properly filled by determining whether the measured current increases during the at least one interval.

52. The method of claim 50, wherein the first predetermined time period is about 25% to about 75% of the at least one interval.

53. A method for evaluating whether an electrochemical test sensor is properly filled, the test sensor including a working electrode electrically coupled to a first lead and a counter electrode electrically coupled to a second lead, the counter electrode including a low-resistance portion and a high-resistance portion, the high-resistance portion including means for increasing electrical resistance such that the high-resistance portion has a greater electrical resistance than the low-resistance portion, the test sensor including a reagent disposed on the working electrode that is adapted to react with glucose in a blood sample for producing an electrochemical reaction indicative of the concentration of the glucose in the fluid test sample, the method comprising:

collecting a fluid test sample;

applying a voltage profile across the first and second leads;

measuring the current profile at the first and second leads in response to the applied voltage profile;

comparing the measured current profile to a predetermined current profile; and

generating an under-filled error signal based on the comparing of the measured current profile to the predetermined profile.

54. The method of claim 53, wherein the predetermine profile is a decay-shaped profile.

55. The method of claim 53, further comprising forming an electrical communication between only the high-resistance portion of the counter electrode and the working electrode when the test sensor is under-filled.