Analyte measurement technique and system

• US 8,709,232 B2
• Filed: 04/30/2012
• Issued: 04/29/2014
• Est. Priority Date: 04/30/2012
• Status: Active Grant

• Current Assignee: LifeScan IP Holdings, LLC
• Original Assignee: Cilag Gmbh International (Johnson & Johnson)
• Inventors: Matzinger, David
• Primary Examiner(s): Van, Luan
• Assistant Examiner(s): ROSENWALD, STEVEN ERIC
• Application Number:
  US13/459,455
• Publication Number:
  US 20130284611A1
• Time in Patent Office: 729 Days
• Field of Search: 20440301-40314, 204/406, 205/777.5
• US Class Current: 205/777.5
• 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

Described are methods and systems to apply a plurality of test voltages to the test strip and measure a current transient output resulting from an electrochemical reaction in a test chamber of the test strip so that highly accurate glucose concentration can be determined.

Claims

1. A method of determining blood glucose concentration with a glucose measurement system that includes a test strip and test meter, the test meter having a microcontroller programmed to apply a plurality of test voltages to the test strip and measure a current transient output resulting from an electrochemical reaction in a test chamber of the test strip, the method comprising:

inserting the test strip into a strip port connector of the test meter to connect at least two electrodes of the test strip to a strip measurement circuit;

initiating a test sequence after deposition of a sample;

applying a first voltage and measuring a first current for a first time duration;

switching the first voltage to a second voltage different than the first voltage;

changing the second voltage to a third voltage different from the second voltage;

measuring a second current output of a current transient from the electrodes after the changing from the second voltage to the third voltage;

estimating a third current that approximates a steady state current output of a current transient after the third voltage is maintained at the electrodes;

calculating a blood glucose concentration based on the first, second and third current outputs of the current transients with an equation of the form;

2. The method of claim 1, in which the measuring of the first current output comprises measuring a current output of the at least two electrodes at about 1.1 seconds after initiation of the test sequence.

3. The method of claim 2, in which the measuring of the second current output comprises measuring a current output of the at least two electrodes at about 4.1 seconds after initiation of the test sequence.

4. The method of claim 2, in which the estimating of the steady state current output comprises measuring a current output of the at least two electrodes at about 5 seconds after initiation of the test sequence.

5. A blood glucose measurement system comprising:

an analyte test strip including;

a substrate having a reagent disposed thereon;

at least two electrodes proximate the reagent in test chamber;

an analyte meter including;

a strip port connector disposed to connect to the two electrodes;

a power supply; and

a microcontroller electrically coupled to the strip port connector and the power supply, the microcontroller programmed to determine a glucose concentration G₁ based on a hematocrit compensation factor and initial glucose proportional current in which the hematocrit compensation factor comprises a ratio that includes the initial glucose proportional current so that at least 97% of corrected test results are within respective bias criterion of ±

10 mg/dL at 65 mg/dL, 240 mg/dL, or at 450 mg/dL as compared to reference YSI data;

±

12 mg/dL at 65 mg/dL, 240 mg/dL, or 450 mg/dL as compared to reference YSI data; and

±

15 mg/dL at 65 mg/dL, 240 mg/dL, or 450 mg/dL as compared to reference YSI data;

the test meter comprising a strip port connector of the test meter to connect at least two electrodes of the test strip to a strip measurement circuit, the strip measurement circuit having a microcontroller programmed to;

apply a plurality of test voltages to the test strip and measure a current transient output resulting from an electrochemical reaction in a test chamber of the test strip;

initiate a test sequence after deposition of a sample by applying a first voltage for a first time duration and measuring a first current;

switch the first voltage to a second voltage different than the first voltage;

change the second voltage to a third voltage different from the second voltage;

measure a second current output of a current transient from the electrodes after the changing from the second voltage to the third voltage;

estimate a third current that approximates a steady state current output of a current transient after the third voltage is maintained at the electrodes;

calculate a blood glucose concentration based on the first, second and third current outputs of the current transients with an equation of the form;