Biosensor methods having enhanced stability and hematocrit performance
First Claim
1. A method of determining the concentration of an analyte in a sample, comprising:
- applying a sample to an electrochemical sensor strip, the senor strip including a first electrode, the first electrode including at least one first layer on a first conductor, the at least one first layer including an enzyme system and at most 8 μ
/mm2 of a mediator,where the mediator assists in transferring electrons between the analyte in the sample and the first conductor;
applying a pulse sequence to the sample, the pulse sequence comprising at least 2 duty cycles within 3 to 14 seconds, where each duty cycle comprises an excitation and a relaxation,where the relaxation of each duty cycle provides an output current reduction to one-half or less of a current flow at an excitation maxima;
determining current measurements from the sample responsive to the pulse sequence; and
determining the concentration of the analyte in the sample from the current measurements, the determined concentration having at least one of a stability bias of less than ±
10%, a hematocrit bias of less than ±
10% for whole blood samples over a 20 to 60% hematocrit range, and an intercept to slope ratio of at most 20 mg/dL.
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Accused Products
Abstract
The present invention relates to electrochemical sensor strips and methods of determining the concentration of an analyte in a sample or improving the performance of a concentration determination. The electrochemical sensor strips may include at most 8 μg/mm2 of a mediator. The strips, the strip reagent layer, or the methods may provide for the determination of a concentration value having at least one of a stability bias of less than ±10% after storage at 50° C. for 4 weeks when compared to a comparison strip stored at −20° C. for 4 weeks, a hematocrit bias of less than ±10% for whole blood samples including from 20 to 60% hematocrit, and an intercept to slope ratio of at most 20 mg/dL. A method of increasing the performance of a quantitative analyte determination also is provided.
57 Citations
18 Claims
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1. A method of determining the concentration of an analyte in a sample, comprising:
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applying a sample to an electrochemical sensor strip, the senor strip including a first electrode, the first electrode including at least one first layer on a first conductor, the at least one first layer including an enzyme system and at most 8 μ
/mm2 of a mediator,where the mediator assists in transferring electrons between the analyte in the sample and the first conductor; applying a pulse sequence to the sample, the pulse sequence comprising at least 2 duty cycles within 3 to 14 seconds, where each duty cycle comprises an excitation and a relaxation, where the relaxation of each duty cycle provides an output current reduction to one-half or less of a current flow at an excitation maxima; determining current measurements from the sample responsive to the pulse sequence; and determining the concentration of the analyte in the sample from the current measurements, the determined concentration having at least one of a stability bias of less than ±
10%, a hematocrit bias of less than ±
10% for whole blood samples over a 20 to 60% hematocrit range, and an intercept to slope ratio of at most 20 mg/dL. - View Dependent Claims (2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, 13, 14, 15, 16, 17, 18)
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Specification