System and method for determining an abused sensor during analyte measurement
First Claim
Patent Images
1. A method for detecting an abused sensor adapted for determining a concentration of a medically significant component of a biological fluid, comprising the steps of:
- a) applying a signal having an AC component to the sensor;
b) measuring an AC response to the signal; and
c) using the AC response to determine if the sensor is abused, wherein steps (a), (b) and (c) are performed before application of the biological fluid to the sensor.
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Accused Products
Abstract
A method of measuring an analyte in a biological fluid comprises applying an excitation signal having a DC component and an AC component. The AC and DC responses are measured; a corrected DC response is determined using the AC response; and a concentration of the analyte is determined based upon the corrected DC response. Other methods and devices are disclosed.
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Citations
8 Claims
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1. A method for detecting an abused sensor adapted for determining a concentration of a medically significant component of a biological fluid, comprising the steps of:
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a) applying a signal having an AC component to the sensor; b) measuring an AC response to the signal; and c) using the AC response to determine if the sensor is abused, wherein steps (a), (b) and (c) are performed before application of the biological fluid to the sensor. - View Dependent Claims (2, 3, 4, 5, 6)
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7. A method for detecting an abused sensor for determining a concentration of a medically significant component of a biological fluid placed upon the sensor, comprising the steps of:
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a) placing the biological fluid sample upon the sensor; b) applying a first signal to the biological fluid; c) measuring a current response to the first signal; d) repeating step (c) at least once; e) calculating a normalized Cottrell Failsafe Ratio using the current response data; f) applying a second signal having an AC component to the biological fluid; g) measuring an AC response to the second signal; and h) combining the normalized Cottrell Failsafe Ratio and the AC response to produce an indication of whether the sensor has been abused, wherein step (h) comprises calculating a FAILSAFE number as follows;
FAILSAFE=1000×
arctan [NCFR/(fs0+fs1(Φ
1−
Φ
2))]where;
1000=scaling factorNCFR normalized Cottrell Failsafe Ratio fs0=constant fs1=constant Φ
1=phase angle at a first frequencyΦ
2=phase angle at a second frequency;wherein a value of FAILSAFE below zero indicates an abused sensor and a value of FAILSAFE above zero indicates a non-abused sensor.
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8. A method of determining a failure condition indicating an abused sensor in a blood glucose concentration test, comprising the steps of:
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a) applying a first test signal having an AC component to a test sample; b) measuring a first phase angle response to the first test signal; c) applying a second test signal having an AC component to the test sample; d) measuring a second phase angle response to the second test signal; and e) determining a failure condition value based upon the first phase angle response the second phase angle response and a predetermined Cottrell Failsafe Ratio, wherein step (e) is performed based at least in part upon evaluating;
arctan [CFR/(fs0+fs1(Φ
A−
Φ
B)]where; CFR=Cottrell Failsafe Ratio fs0=a constant fs1=a constant Φ
A=first phase angle responseΦ
B=second phase angle response.
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Specification