ANALYTE MEASUREMENT METHOD AND SYSTEM WITH ERROR TRAPPING

• US 20130217053A1
• Filed: 09/28/2011
• Published: 08/22/2013
• Est. Priority Date: 09/28/2010
• Status: Active Grant

• Current Assignee: Cilag Gmbh International (Johnson & Johnson)
• Original Assignee: LifeScan Scotland Limited (Johnson & Johnson)
• Inventors: Mackintosh, Stephen, McColl, David
• Granted Patent: US 9,618,517 B2
• Time in Patent Office: Days
• US Class Current: 435/14
• 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 33/66 involving blood sugars, e.g. galactose

Abstract

Described and illustrated herein are systems and exemplary methods of operating an analyte measurement system having a meter and a test strip. The methods and systems describe herein allow for trapping various errors during calculation of the analyte due to variations in the structure and materials making up the test strip and ambient temperatures.

Claims

1. A method for determining a glucose concentration with a system having a test strip and a meter having a test circuit including a microprocessor, the method comprising:

initiating a chemical reaction between a reference electrode and a second working electrode coated with a reagent layer and between the reference electrode and a first working electrode coated with a reagent layer of the test strip;

measuring a primary test current and a secondary test current on one of the first and second working electrodes;

determining whether a difference between the primary test current and secondary test current is less than zero; and

upon the determining being true, deriving a glucose concentration based on the plurality of test currents else otherwise returning an error.

2. The method of claim 1, in which the primary test current comprises a current being sampled at about an initiation of the sampling step.

3. The method of claim 1, in which the secondary test current comprises a current being sampled at about 0.8 seconds after the initiation of the sampling step.

4. The method of claim 1, further comprising

determining a current ratio from respective tertiary test currents sampled from each of the second and first working electrodes;

and

upon the current ratio of the second working electrode to the first working electrode being greater than about K, bypassing the deriving step.

5. The method of claim 4, in which K comprises a constant from about 1 to about 2.

6. The method of claim 4, in which K comprises a constant of about 1.4.

10. The method of any one of claims 1, 7, or 9, in which the plurality of measured or sampled test currents comprises first, second, third, fourth, and fifth test currents and K comprises a value from about 1.0 to about 1.4.

11. The method of claim 10, in which the first test current comprises a test current measured from about 0.98 to about 1.00 seconds after initiation of the measuring.

12. The method of claim 10, in which the second current comprises a test current measured from about 1.98 to about 2.00 seconds after initiation of the measuring.

13. The method of claim 10, in which the third current comprises a test current measured from about 2.43 to about 2.45 seconds after initiation of the measuring.

14. The method of claim 10, in which the fourth current comprises a test current measured from about 2.61 to about 2.63 seconds after initiation of the measuring.

15. The method of claim 10, in which the fifth current comprises a test current measured from about 2.70 to about 2.72 seconds after initiation of the measuring.

16. The method of claim 10, in which the deriving comprises calculating a value representative of glucose concentration with an equation of the form:

17. The method of claim 16, in which first tuning parameter comprises a value from about 9.9 to about 10.2 and second tuning parameter comprises a value from about 10.8 to about 11.2.

7. A method for determining a glucose concentration with a system having a test strip and a meter having a test circuit including a microprocessor, the method comprising:

initiating a chemical reaction between a reference electrode and a second working electrode coated with a reagent layer and between the reference electrode and a first working electrode coated with a reagent layer of the test strip;

sampling a plurality of test currents after a blood sample is applied to the test strip;

determining a current ratio from respective tertiary test currents sampled from each of the second and first working electrodes; and

querying as to whether the current ratio of the second working electrode to the first working electrode is less than about K, and if true, deriving a glucose concentration based on the plurality of test currents else otherwise returning an error.

8. The method of claim 7, further comprising:

measuring a primary test current and a secondary test current on one of the first and second working electrodes;

determining whether a difference between the primary test current and secondary test current is less than about zero; and

upon the determining being true, terminating the deriving step.

9. A method for determining a glucose concentration with a system having a test strip and a meter having a test circuit including a microprocessor, the method comprising:

initiating a chemical reaction between a reference electrode and a second working electrode coated with a reagent layer and between the reference electrode and a first working electrode coated with a reagent layer of the test strip;

measuring a primary test current and a secondary test current on one of the first and second working electrodes;

determining whether a difference between the primary test current and secondary test current is less than zero;

determining a current ratio from respective tertiary test currents sampled from each of the second and first working electrodes;

evaluating whether a current ratio from respective tertiary test currents sampled from each of the second and first working electrodes is greater than about K; and

upon either or both of the determining step or evaluating step being true, returning an error otherwise deriving a glucose concentration based on the plurality of test currents.