Underfill Detection System For A Biosensor
First Claim
1. A method for detecting an underfill condition in a biosensor, comprising:
- applying a test excitation signal to a sample of a biological fluid;
switching the test excitation signal to at least one different amplitude, during at least one of a start of the test excitation signal, a test pulse, and a transition from one test pulse to another test pulse;
measuring a test output signal from the sample; and
comparing the test output signal with at least one underfill threshold; and
detecting an underfill condition in the biosensor from the comparison of the test output signal with the at least one underfill threshold.
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Accused Products
Abstract
A biosensor has an underfill detection system that determines whether a sample of a biological fluid is large enough for an analysis of one or more analytes. The underfill detection system applies an excitation signal to the sample, which generates an output signal in response to the excitation signal. The underfill detection system switches the amplitude of the excitation signal. The transition of the excitation signal to a different amplitude changes the output signal when the sample is not large enough for an accurate and/or precise analysis. The underfill detection system measures and compares the output signal with one or more underfill thresholds to determine whether an underfill condition exists.
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Citations
52 Claims
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1. A method for detecting an underfill condition in a biosensor, comprising:
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applying a test excitation signal to a sample of a biological fluid; switching the test excitation signal to at least one different amplitude, during at least one of a start of the test excitation signal, a test pulse, and a transition from one test pulse to another test pulse; measuring a test output signal from the sample; and comparing the test output signal with at least one underfill threshold; and detecting an underfill condition in the biosensor from the comparison of the test output signal with the at least one underfill threshold. - View Dependent Claims (2, 5, 6, 7, 9, 10, 11, 12, 13, 14, 15, 16)
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3. (canceled)
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4. (canceled)
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8. (canceled)
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17-30. -30. (canceled)
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31. A biosensor for determining an analyte concentration in a biological fluid, comprising:
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a sensor strip having a sample interface on a base, where the sample interface is adjacent to a reservoir formed by the base; a measuring device having a processor connected to a sensor interface, where the sensor interface has electrical communication with the sample interface; and where the processor applies a test excitation signal to the sample interface, where the processor switches the test excitation signal to at least one different amplitude during at least one of a start of the test excitation signal, a test pulse, and a transition from one test pulse to another test pulse, where the processor measures a test output signal from the sample interface, and where the processor compares the test output signal to at least one underfill threshold to determine if the sensor strip is underfilled.
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32-45. -45. (canceled)
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46. A method for detecting an underfill condition in a biosensor, comprising:
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applying a test excitation signal to a sample of a biological fluid, where the test excitation signal includes at least first and second test pulses separated by a test relaxation; measuring a first test output signal from the first test pulse; measuring a second test output signal from the second test pulse; comparing a difference between the first and second test output signals with at least one underfill threshold; and detecting an underfill condition in the biosensor from the comparison of the difference with the at least one underfill threshold.
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47. A method for detecting an underfill condition in a biosensor, comprising:
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applying a test excitation signal to a sample of a biological fluid; measuring a first test output signal from the sample; measuring a second test output signal from the sample; determining if at least one test output signal is equal to or less than a first underfill threshold; determining if a difference between the first and second test output signals is equal to or greater than a second underfill threshold; and detecting an underfill condition in the biosensor from at least one of the determinations.
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48. A method for determining an analyte concentration in a biological fluid, comprising:
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applying a test excitation signal to a sample of a biological fluid in a biosensor during a test period, the test excitation signal comprising a sequence of test pulses separated by test relaxations; measuring at least one test output signal from the sample in response to the test excitation signal; comparing the at least one test output signal with at least one underfill threshold; and determining whether an underfill condition exists based on the comparison; where, if an underfill condition does exist, the biosensor generates an error signal, and if an underfill condition does not exist, the biosensor proceeds with an analysis of the analyte in the biological fluid, the analysis comprising; measuring an assay output signal from the sample, generated in response to the test excitation signal; and correlating the assay output signal with a concentration of the analyte in the biological fluid to provide a determined analyte concentration; where, when the method is performed with a plurality of samples, at least 98% of the determined analyte concentrations are within 15% of a reference value of the analyte concentration. - View Dependent Claims (49, 50, 51)
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52. A method for determining an analyte concentration in a sample of a biological fluid, comprising:
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detecting an application of the sample to a biosensor, the detecting comprising applying a polling excitation signal to a biosensor, measuring a polling output current from the biosensor, determining if the polling output current exceeds a polling threshold, and measuring another polling output current from the biosensor after a first delay; starting a time count; applying a pulse sequence to the biosensor, the pulse sequence comprising applying a first pulse, measuring a first series of sensor currents in response the first pulse, applying a second pulse, measuring a second series of sensor currents in response the second pulse, applying a third pulse after a second delay, measuring a third series of sensor currents in response the third pulse, applying a fourth pulse after a third delay, measuring a fourth series of sensor currents in response the fourth pulse, applying a fifth pulse after a fourth delay, and measuring a fifth series of sensor currents in response the fifth pulse; adjusting a slope value and an intercept value of a calibration for the biosensor for a temperature effect; calculating a glucose concentration of the sample using the adjusted calibration; and checking for underfill of the sample in the biosensor, the checking comprising setting an error mode to “
underfill”
if a last measured current in the second series is less than a current threshold for underfill, orsetting an error mode to “
underfill”
if the difference of a last measured current in the first series and a first measured current in the second series is greater than a current delta threshold for underfill.
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Specification