System and method of processing a current sample for calculating a glucose concentration

• US 7,468,125 B2
• Filed: 10/17/2005
• Issued: 12/23/2008
• Est. Priority Date: 10/17/2005
• Status: Active Grant

• Current Assignee: Cilag Gmbh International (Johnson & Johnson)
• Original Assignee: Lifescan Incorporated (Duv Holding Corporation)
• Inventors: Ebner, Manfred, Kraft, Ulrich, Christol, James
• Primary Examiner(s): NOGUEROLA, ALEXANDER STEPHAN
• Application Number:
  US11/252,216
• Publication Number:
  US 20070087397A1
• Time in Patent Office: 1,163 Days
• Field of Search: 20440301-40315, 204/406, 204416-420, 205/777.5, 205/778, 205/792, 205/775
• US Class Current: 205/792
• 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

A system and method of processing a test current for an analyte measurement in a fluid using a test strip and a test meter are disclosed. The method comprises sampling the test current at a pre-determined sampling rate to acquire a plurality of A/D conversions. The method also comprises filtering out at least a highest magnitude A/D conversion and a lowest magnitude A/D conversion leaving a plurality of accepted A/D conversions. Further, the method comprises calculating an average or a summation of the plurality of accepted A/D conversions and converting the average or the summation into a glucose concentration.

Claims

1. A method of determining analyte concentration in a physiological fluid, comprising:

receiving, by a test meter, a sample of physiological fluid;

causing a current to run through the fluid sample;

sampling the magnitude of the current a plurality of times to form a plurality of analog to digital (A/D) conversions;

discarding a subset of the plurality of A/D conversion, based on the magnitudes;

generating an analyte concentration based on the remaining A/D conversions;

determining a maximum current peak time;

determining a change in current after the maximum current peak time during a time interval; and

selectively indicating an error based on the change in current.

9. The method of one of claims 1, 2, 3 or 8, wherein the step of discarding a subset of the plurality of A/D conversions comprises filtering out at least a highest magnitude A/D conversion and a lowest magnitude A/D conversion leaving a plurality of accepted A/D conversions.

10. The method of one of claims 1, 2, 3 or 8, wherein the step of generating an analyte concentration based on the remaining A/D conversions comprises:

calculating an average or a summation of said plurality of accepted A/D conversions; and

converting said average or said summation into an analyte concentration.

11. The method according to one of claims 1, 2, 3 or 8, further comprising

identifying the presence of the fluid in apposition to be detectable by the meter;

and

determining whether the identification is in error.

2. A method of determining analyte concentration in a physiological fluid, comprising:

receiving, by a test meter, a sample of physiological fluid;

causing a current to run through the fluid sample;

sampling the magnitude of the current a plurality of times to form a plurality of analog to digital (A/D) conversions;

discarding a subset of the plurality of A/D conversion, based on the magnitudes; and

generating an analyte concentration based on the remaining A/D conversions, wherein a first subset of the plurality of A/D conversions is sampled from a first pair of electrodes and a second subset of the plurality of A/D conversions is sampled from a second pair of electrodes.

3. A method to determine analyte concentration in a fluid sample in contact with two electrodes, the method comprising:

applying a voltage to the electrodes;

sampling the magnitude of current generated in the fluid sample to provide a plurality of analog-to-digital conversions;

discarding a subset of the plurality of analog-to-digatal conversions;

generating an analyte concentration based on remaining analog-to digital conversions;

determining a maximum current peak time;

determining a change in current after the maximum current peak time during a time interval; and

selectively indicating an error based on the change in current.

4. The method of claim 3, wherein the step of generating an analyte concentration based on the remaining A/D conversions comprises:

repeating the steps of sampling, discarding and generating more than once to calculate a total more than one current samples; and

summing together said more than one current samples to form a current reading.

5. The method of claim 4, further comprising:

repeating the steps of repeating and summing at least one more times to calculate a total at least two current readings;

summing together said at least two current readings to form a final current value; and

calculating a glucose concentration based on said final current value.

6. The method of claim 3, wherein the sampling comprises sampling 16 analog-to-digital conversions during a current time sampling interval.

7. The method of claim 6, wherein the discarding comprises filtering out four highest analog-to-digital conversions and four lowest analog-to-digital conversions so as to provide eight analog-to-digital conversions for determination of analyte concentration.

8. A method to determine analyte concentration in a fluid sample in contact with two electrodes, the method comprising:

applying a voltage to the electrodes;

sampling the magnitude of current generated in the fluid sample to provide a plurality of analog-to-digital conversions;

discarding a subset of the plurality of analog-to-digital conversions;

generating an analyte concentration based on remaining analog-to-digital conversion, wherein a first subset of the plurality of A/D conversions is sampled from a first pair of electrodes and a second subset of the plurality of A/D conversions is sampled from a second pair of electrodes.