Accurate analyte measurements for electrochemical test strip based on sensed physical characteristic(s) of the sample containing the analyte

Patent metadata

Field	Value
Publication number	US-9903830-B2
Application number	US-201214353870-A
Country	US
Kind code	B2
Filing date	Dec 18, 2012
Priority date	Dec 29, 2011
Publication date	Feb 27, 2018
Grant date	Feb 27, 2018

Abstract

Various embodiments for methods and systems that allow for a more accurate analyte concentration with a biosensor by determining at least one physical characteristic of the sample containing the analyte and deriving one of a batch slope, sampling time, or combinations thereof to attain accurate glucose concentration.

First claim

The invention claimed is:

1. A method of demonstrating increased accuracy of a test strip, the method comprising:
providing a batch of test strips;
introducing a referential sample containing a referential concentration of an analyte to each test strip of the batch of test strips to initiate a test sequence;
reacting the analyte with a reagent on each test strip to cause a physical transformation of the analyte;
determining a physical characteristic of the referential sample;
deriving a defined batch slope for the batch of test strips based on the determined physical characteristics of the referential sample for selected test strips from the batch of test strips;
determining an approximate analyte concentration of the referential analyte concentration as being in one of a low glucose range, a medium glucose range or a high glucose range;
determining a sampling time point based on the approximate analyte concentration of the referential analyte concentration, the determined sampling time point being selected as a first sampling time point responsive to the approximate analyte concentration being in the low glucose range, a second sampling time point responsive to the approximate analyte concentration being in the medium glucose range, and a third sampling time point responsive to the approximate analyte concentration being in the high glucose range;
sampling an electrical output of the referential sample at the determined sampling time point during the test sequence;
calculating an analyte concentration based on the defined batch slope, the determined sampling time point and sampled electrical output to provide for a final analyte concentration value for each test strip of the batch of test strips such that at least 95% of the final analyte concentration values of the batch of test strips are within ±15% of the referential analyte concentration.

2. The method of claim 1 , in which the determining comprises applying a first signal to the sample to measure the physical characteristic of the sample.

3. The method of claim 2 , in which the sampling comprises driving a second signal to the sample.

4. The method of claim 3 , in which the applying of the first signal and the driving of the second signal is in sequential order.

5. The method of claim 3 , in which the applying of the first signal overlaps with the driving of the second signal.

6. The method of claim 2 , in which the applying of the first signal comprises directing an optical signal to the sample so that a physical characteristic of the sample is determined from an output of the optical signal.

7. The method of claim 2 , in which the applying of the first signal comprises directing an alternating signal to the sample so that a physical characteristic of the sample is determined from an output of the alternating signal.

8. The method of claim 2 , in which the applying of the first signal comprises driving first and second alternating signals at different respective frequencies in which a first frequency is lower than the second frequency.

9. The method of claim 8 , in which the first frequency is at least one order of magnitude lower than the second frequency.

10. The method of claim 8 , in which the first frequency comprises any frequency in the range of about 10 kHz to about 250 kHz.

11. The method of claim 1 , in which the physical characteristic comprises at least one of viscosity, hematocrit, temperature, and density of the sample, or combinations thereof.

12. The method of claim 1 , in which the physical characteristic comprises hematocrit and the analyte comprises glucose.

13. The method of claim 1 , in which the deriving comprises calculating a batch slope from an equation of the form:
x=aH 2 +bH+c
where
x represents a derived batch slope from the deriving step;
H represents the measured, determined or estimated physical characteristic of the sample;
a represents about 1.4e−6,
b represents about −3.8e−4,
c represents about 3.6e−2.

14. The method of claim 13 , in which the calculating of the analyte concentration comprises utilizing an equation of the form:

G
0

=

[

I
E

-
Intercept

x

]

where
G 0 represents an analyte concentration
I E represents, or is, a signal (value or measurement; proportional to analyte concentration) measured at a predetermined or specified sampling time;
Intercept represents a calibration parameter for a batch of biosensors;
x represents a derived batch slope from the deriving step.

15. The method of claim 14 , in which the predetermined time is about 2.5 seconds after a start of the test sequence.

Assignees

• Lifescan Scotland Ltd

Inventors

• Malecha Michael
• Smith Antony
• Mccoll David

Classifications

• G16B40/00

  ICT specially adapted for biostatistics; ICT specially adapted for bioinformatics-related machine learning or data mining, e.g. knowledge discovery or pattern finding · CPC title

• G01N27/26

  by investigating electrochemical variables; by using electrolysis or electrophoresis · CPC title

• G01N27/3272

  Test elements therefor, i.e. disposable laminated substrates with electrodes, reagent and channels (optical biosensors G01N33/52) · CPC title

• G01N27/3274 Primary

  Corrective measures, e.g. error detection, compensation for temperature or hematocrit, calibration (coding of calibration information G01N33/48771) · CPC title

• G01N27/327 Primary

  Biochemical electrodes {, e.g. electrical or mechanical details for in vitro measurements} · CPC title