Underfill Management System for a Biosensor

• US 20110297557A1
• Filed: 06/07/2011
• Published: 12/08/2011
• Est. Priority Date: 06/07/2010
• Status: Active Grant

• Current Assignee: Ascensia Diabetes Care Holdings AG (PHC Holdings Corporation)
• Original Assignee: Bayer Healthcare LLC (Bayer AG)
• Inventors: Wu, Huan-Ping, Maurer, Eric
• Granted Patent: US 9,222,910 B2
• Time in Patent Office: Days
• US Class Current: 205/792
• CPC Class Codes: G01N 27/327 Biochemical electrodes , e.g. electrical or mechanical details for in vitro measurements
• 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 27/4163 checking the operation of, or calibrating, the measuring apparatus G01N27/3274, G01N27/4175 and G01N33/0006 take precedence
• CPC Class Codes: G01N 33/48771 Coding of information, e.g. calibration data, lot number

Abstract

A biosensor system including the underfill management system determines the analyte concentration in a sample from the at least one analytic output signal value. The underfill management system includes an underfill recognition system and an underfill compensation system. The underfill recognition system determines whether the test sensor initially is substantially full-filled or underfilled, indicates when the sample volume is underfilled so that additional sample may be added to the test sensor, and starts or stops the sample analysis in response to the sample volume. The underfill recognition system also may determine the initial degree of underfill. After the underfill recognition system determines the initial fill state of the test sensor, the underfill compensation system compensates the analysis based on the initial fill state of the test sensor to improve the measurement performance of the biosensor system for initially underfilled test sensors.

Claims

1. A method for determining an analyte concentration in a sample, comprising:

determining a fill state of a test sensor;

signaling for the addition of additional sample to substantially full-fill the test sensor;

applying an analytic test excitation signal to the sample;

generating at least one analytic output signal value responsive to the concentration of the analyte in the sample and the analytic test excitation signal;

compensating underfill error in the at least one analytic output signal value in response to the fill state of the test sensor; and

determining an analyte concentration in the sample from the at least one output signal value and the compensating.

2. The method of claim 1, further comprising detecting sample presence in the test sensor before determining the fill state of the test sensor.

3. The method of claim 1, where

the determining the fill state of the test sensor includes determining the initial fill state of the test sensor, and where

the compensating the underfill error in the at least one analytic output signal value in response to the fill state of the test sensor is responsive to the initial fill state of the test sensor.

4. The method of claim 1, where the determining the fill state of the test sensor includes

applying a polling sequence to the sample, where preferably the polling sequence includes regular and extended polling sequences and the extended polling sequence includes at least one different extended input pulse, or

sequentially detecting sample filling.

5. The method of claim 4, where the at least one different extended input pulse includes two or more different extended input pulses of decreasing amplitude.

6. The method of claim 4, where the sequentially detecting includes determining when two different pairs of electrodes are contacted by the sample.

7. The method of claim 4, further comprising adjusting at least one reference correlation with at least one index function, where the compensating the underfill error includes determining the at least one index function from an error parameter.

8. The method of claim 7, where the at least one index function is responsive to a slope deviation between a reference correlation and a hypothetical sample analyte concentration.

9. The method claim 7, further comprising

selecting the error parameter in response to the polling sequence or the sequential detecting, where

preferably the error parameter is a value responsive to a volume threshold.

10. The method of claim 9, where the error parameter is a value corresponding to a duration.

11. The method of claim 1, where the compensating the underfill error includes a subsequently substantially full-fill underfill compensation system including a different primary function than used for an initial substantially full-fill compensation.

12. The method of claim 1, where the compensating the underfill error includes an initial low volume underfill compensation system including a different first residual function than used for initial substantially full-fill compensation.

13. The method of claim 12, where the initial low volume underfill compensation system further includes a primary function used for initial substantially full-fill compensation.

14. The method of claim 1, where the compensating the underfill error includes an initial high volume underfill compensation system including a different primary function than used for an initial substantially full-fill compensation.

15. The method of claim 1, where the sample is whole blood including red blood cells and the analyte is glucose, and greater than 95% of the glucose concentrations determined for 600 or fewer analyses fall within a ±

10% percent bias limit.

16. The method of claim 15, where the greater than 95% of the glucose concentrations determined for 600 or fewer analyses fall within a ±

10% percent bias limit when a test sensor is initially underfilled and subsequently substantial full-fill within 35 seconds or less from the initial fill.

17. The method of claim 1, where the sample is whole blood including red blood cells and the analyte is glucose, and greater than 75% of the glucose concentrations determined for 600 or fewer analyses fall within a ±

5% percent bias limit.

18. The method of claim 1, where the sample is whole blood including red blood cells and the analyte is glucose, and the glucose concentrations determined for 600 or fewer analyses provide a percent bias standard deviation of less than 5.

19. A biosensor system, for determining an analyte concentration in a sample, comprising:

a test sensor having a sample interface in electrical communication with a reservoir formed by the test sensor; and

a measurement device having a processor connected to a sensor interface, the sensor interface having electrical communication with the sample interface, and the processor having electrical communication with a storage medium,

where the processor performs the method of claim 1,

where preferably the storage medium stores at least one reference correlation pre-determined with a reference instrument, and

where preferably the measurement device is portable.

20. A method for determining an analyte concentration in a sample, comprising:

applying a regular polling sequence and an extended polling sequence to the sample, the extended polling sequence including at least one different extended input pulse;

generating at least one analytic output signal responsive to the concentration of the analyte in the sample;

selecting an error parameter responsive to the at least one different extended input pulse;

determining at least one index function responsive to the error parameter; and

determining the analyte concentration in the sample from the at least one analytic output signal and a slope compensation equation responsive to the at least one index function, where the slope compensation equation includes at least one reference correlation and at least one slope deviation.

21-24. -24. (canceled)

25. A method for determining an analyte concentration in a sample, comprising:

sequentially detecting sample filling of a test sensor, where the sequentially detecting includes determining when two different pairs of electrodes of the test sensor are contacted by the sample;

generating at least one analytic output signal responsive to the concentration of the analyte in the sample;

selecting an error parameter responsive to when the two different pairs of electrodes of the test sensor are contacted by the sample;

determining at least one index function responsive to the error parameter; and

determining the analyte concentration in the sample from the at least one analytic output signal and a slope compensation equation responsive to the at least one index function, where the slope compensation equation includes at least one reference correlation and at least one slope deviation.

26-29. -29. (canceled)