Analysis Compensation Including Segmented Signals

• US 20130071869A1
• Filed: 09/20/2012
• Published: 03/21/2013
• Est. Priority Date: 09/21/2011
• Status: Active Grant

• Current Assignee: Ascensia Diabetes Care Holdings AG (PHC Holdings Corporation)
• Original Assignee: Bayer Healthcare LLC (Bayer AG)
• Inventors: Wu, Huan-Ping
• Granted Patent: US 9,775,806 B2
• Time in Patent Office: Days
• US Class Current: 435/25
• CPC Class Codes: A61K 31/198 Alpha-amino acids, e.g. alanine or edetic acid [EDTA] betaine A61K31/205; proline A61K31/401; tryptophan A61K31/405; histidine A61K31/4172; peptides not degraded to individual amino acids A61K38/00
• CPC Class Codes: A61K 47/26 Carbohydrates, e.g. sugar alcohols, amino sugars, nucleic acids, mono-, di- or oligo-saccharides; Derivatives thereof, e.g. polysorbates, sorbitan fatty acid esters or glycyrrhizin
• CPC Class Codes: A61K 9/0019 Injectable compositions; Intramuscular, intravenous, arterial, subcutaneous administration; Compositions to be administered through the skin in an invasive manner non-active ingredients are additionally classified in A61K47/00
• CPC Class Codes: A61K 9/19 lyophilised , i.e. freeze-dried, solutions or dispersions lyophilised products with subsequent particle size reduction A61K9/14; granules or pellets made by lyphilisation A61K9/1682; solid oral dosage forms made by lyophilisation A61K9/2095; lyophilisation additives A61K47/00
• 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 biosensor system determines analyte concentration from an output signal generated from a light-identifiable species or a redox reaction of the analyte. The biosensor system compensates at least 50% of the total error in the output signal with a primary function and may compensate a portion of the residual error with at least one residual function. An SSP function may serve as the primary function, first residual function, or second residual function. Preferably, when the SSP function serves as the first residual function, the SSP function compensates at least 50% of the residual error remaining after primary compensation. Preferably, when the SSP function serves as the second residual function, the SSP function compensates at least 50% of the residual error remaining after primary and first residual compensation. The error compensation provided by the primary, first residual, and second residual functions may be adjusted with function weighing coefficients.

Claims

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

applying an input signal to a sample including an analyte;

generating an output signal responsive to a concentration of the analyte in the sample and the input signal;

determining a compensated value from the output signal in response to a conversion function and a segmented signal processing function; and

determining the analyte concentration in the sample from the compensated value.

2. The method of claim 1, where the output signal is responsive to a concentration of a measurable species in the sample and the concentration of the measurable species in the sample is responsive to the concentration of the analyte in the sample.

3. The method of claim 2, where the concentration of the measurable species in the sample is responsive to a chemical reaction between the analyte, an enzyme, and a mediator, where the chemical reaction is a redox reaction.

4. The method of claim 2, where the measurable species is light-identifiable.

5. The method of claim 1, further comprising continuously applying the input signal to the sample until an analysis end-point is reached.

6. The method of claim 5, further comprising measuring at least three output signal values from the output signal.

7. The method of claim 1, where the input signal is gated and includes at least two excitations, where each excitation is applied until an intermediate analysis end-point is reached.

8. The method of claim 7, further comprising measuring at least two output signal values from the output signal of each of the at least two excitations.

9. The method of claim 1, where the segmented signal processing function is predetermined and includes at least two segmented signal processing parameters generated from the output signal.

10. The method of claim 9, where the at least two segmented signal processing parameters are determined from the output signal with a parameter determining method selected from the group consisting of averaging of signals within a segment, determining ratios of the signal values from within a segment, determining differentials of the signal values from within a segment, determining time base differentials, determining normalized differentials, determining time-based normalized differentials, determining one or more decay constants, and determining one or more decay rates.

11. The method of claim 9, where the at least two segmented signal processing parameters are determined using a parameter determining method selected from the group consisting of determining differentials of the signal values from within a segment, determining time base differentials, determining normalized differentials, and determining time-based normalized differentials.

12. The method of claim 9, where the at least two segmented signal processing parameters are determined using a parameter determining method selected from the group consisting of determining time base differentials and determining time-based normalized differentials.

13. The method of claim 9, where the segmented signal processing parameters are determined from the output signal and a parameter determining method, where the parameter determining method segments a substantially continuous output signal before an end-point value.

14. The method of claim 1, where the input signal is gated and the segmented signal processing parameters are determined from the output signal and a parameter determining method, where the parameter determining method segments at least a first output signal before a first intermediate end-point value of the first output signal and a second output signal before a second intermediate end-point value of the second output signal.

15. The method of claim 1, further comprising:

converting the output signal with the conversion function before applying the segmented signal processing function, where the conversion function includes a reference correlation relating the output signal to known sample analyte concentrations.

16. The method of claim 1, where the analyte concentration determined from the compensated value includes 30% less relative error than if the analyte concentration were determined from the output signal and the conversion function without the segmented signal processing function.

17. The method of claim 1, where the analyte concentration determined from the compensated value includes 30% less relative error than if the analyte concentration were determined from the output signal and the conversion function without the segmented signal processing function.

18. The method of claim 15, where the determining the compensated value from the output signal in response to the conversion function and the segmented signal processing function, further comprises determining the compensated value from the output signal in response to a primary function, where the segmented signal processing function is not the primary function.

19. The method of claim 18, where error described by the segmented signal processing function is substantially different than error described by the primary function.

20. The method of claim 18, further comprising modifying the segmented signal processing function and the primary function with function weighing coefficients.

21. The method of claim 18, where the primary function includes an index function, where the index function relates at least three error parameters to a previously determined expression of total error.

22. The method of claim 18, where the segmented signal processing function describes at least 50% of residual error in the compensated value after the primary function compensates the output signal.

23. The method of claim 18, where the index function is complex, the complex index function comprising:

at least one term having a hematocrit error parameter, and

at least one term having a temperature error parameter.

24. The method of claim 23, where the complex index function includes a first term and a second term, where the first and the second terms are each modified by a different complex index function term weighing coefficient, the first and the second terms each include an error parameter, and the error parameters are independently selected from intermediate output signal values, values external to the output signal, or both.

25. The method of claim 18, where the method further comprises determining the compensated value from the output signal in response to a residual function, where the residual function is not the segmented signal processing function, and where the residual function is not the primary function.

26. The method of claim 25, further comprising modifying the segmented signal processing function, the primary function, and the residual function with function weighing coefficients.

27. The method of claim 25, where error described by the segmented signal processing function is substantially different error than error described by the residual function, and where error described by the segmented signal processing function is substantially different than error described by the primary function.

28. The method of claim 1, where the segmented signal processing function includes an index function relating at least a first and a second term to a previously determined expression of total error.

29. The method of claim 28, where the index function is complex, the at least two terms are segmented signal processing parameters independently selected from segmented output signal values, and where each of the at least two terms are modified by a different complex index function term weighing coefficient.

30. The method of claim 28, where the index function is complex, the complex index function including

at least one term having a hematocrit error parameter or a hemoglobin error parameter, and

at least one term having a temperature error parameter.

31. The method of claim 30, where the first and the second terms are each modified by a different complex index function term weighing coefficient, the first and the second terms each include a segmented signal processing parameter, and the segmented signal processing parameters are independently selected from segmented output signal values.

32. The method of claim 1, where the sample is blood and the analyte is glucose.

33. The method of claim 1, where the determining the compensated value includes altering a reference correlation of the conversion function with a change in slope value determined from the signal processing function, where the reference correlation relates the output signal to known sample analyte concentrations.

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

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

a measurement device having a processor connected to a sensor interface through a signal generator, the sensor interface having electrical or optical communication with the sample interface, and the processor having electrical communication with a storage medium,

where the processor instructs the signal generator to apply an electrical or optical input signal to the sensor interface,

where the processor determines an output signal responsive to the input signal and the concentration of the analyte in the sample from the sensor interface,

where the processor compensates at least 500 of the total error in the output signal with a primary function,

where if the primary function is not an segmented signal processing function, the processor compensates at least 5% of the remaining error in the output signal with a segmented signal processing function,

where the processor determines a compensated value, and

where the processor determines an analyte concentration in a sample from the compensated value.

35-37. -37. (canceled)

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

generating an output signal responsive to a concentration of an analyte in a sample and an input signal;

compensating the output signal with a segmented signal processing function; and

determining the analyte concentration in the sample from the compensated output signal.

39. A method of determining a desired segmented signal processing function for compensating an analyte concentration of a sample, comprising:

generating an output signal responsive to a concentration of an analyte in a sample, where the output signal includes an end-point reading;

segmenting the output signal with a regular or irregular segmenting interval with respect to time into at least three output signal segments;

converting the at least three output signal segments into at least three segmented signal processing parameters;

selecting multiple segmented signal processing parameters as potential terms in a segmented signal processing function, the segmented signal processing parameters describing at least a portion of the total error in the output signal;

determining a first exclusion value for the potential terms;

applying an exclusion test responsive to the first exclusion value for the potential terms;

identifying one or more of the potential terms for exclusion from the segmented signal processing function;

excluding one or more identified potential terms from the segmented signal processing function; and

determining a desired segmented signal processing function.