Gated Amperometry Methods
AssigneeBayer HealthCare LLC
InventorsHuan-Ping Wu, Christine D. Nelson, Greg P. Beer
Life of this patent
Estimating the term…
Abstract
A sensor system, device, and methods for determining the concentration of an analyte in a sample is described. Gated amperometric pulse sequences including multiple duty cycles of sequential excitations and relaxations may provide a shorter analysis time and/or improve the accuracy and/or precision of the analysis. The disclosed gated amperometric pulse sequences may reduce analysis errors arising from the hematocrit effect, variance in cap-gap volumes, non-steady-state conditions, mediator background, under-fill, temperature changes in the sample, and a single set of calibration constants.
Claims34
A method of reducing bias attributable to mediator background in a determined concentration of an analyte in a sample comprising:
- generating a measurable species from a mediator, the concentration of the measurable species responsive to a concentration of an analyte in a sample;
- applying an input signal to the sample, the input signal comprising at least 3 duty cycles within 180 seconds and each duty cycle comprising an excitation and a relaxation,
- where the input signal has a redox intensity of at least 0.01 if continued for a 10 second duration,
- where the relaxations of the at least 3 duty cycles each provide an independent diffusion and analyte reaction time during which the analyte generates the measurable species;
- measuring an output signal from at least one amperometric excitation of the at least 3 duty cycles,
- the output signal responsive to the concentration of the measurable species in the sample, and
- the at least one amperometric excitation having a duration from 0.01 second to 1.5 seconds;
- and
- determining the concentration of the analyte in the sample having reduced bias attributable to mediator background in response to the measured output signal, where the determined concentration is responsive to a rate at which the measurable species is oxidized or reduced by the input signal.
A method of signaling a user to add additional sample to a sensor strip, comprising:
- applying an input signal to a sample contacting working and counter electrodes of a sensor strip, the input signal including at least 3 duty cycles within 180 seconds and each duty cycle comprising an excitation and a relaxation;
- measuring an output signal including currents from the excitations of at least two of the at least 3 duty cycles;
- determining a decay constant profile from the measured output signal for the at least two excitations;
- determining if the sensor strip is under-filled from the decay constant profiles determined from the at least two excitations;
- signaling the user to add additional sample to the sensor strip when the sensor strip is under-filled;
- and
- determining a concentration of an analyte in the sample from the output signal.
-32. (canceled)
A method of determining the temperature of a sample contained by a sensor strip, comprising:
- previously determining correlations between decay rate and temperature;
- determining a current profile from currents recorded during at least two excitations of an input signal including at least 3 duty cycles within 180 seconds;
- correlating the current profile to the correlations between decay rate and temperature to determine the temperature of the sample.
-37. (canceled)
A method of determining the duration of an input signal to apply to a sample, for determining the concentration of an analyte in the sample, the method comprising:
- previously determining multiple sets of calibration constants from currents recorded at fixed times from an output signal;
- applying an input signal including at least 3 duty cycles within 180 seconds to the sample, where each of the at least 3 duty cycles includes an excitation;
- and
- determining a concentration of the analyte in the sample from an output signal measured from the excitation of at least one of the at least 3 duty cycles;
- determining the duration of the input signal to apply to the sample in response to the determined concentration of the analyte in the sample.
-49. (canceled)
A handheld measuring device, for determining the concentration of an analyte in a sample, where
- the device is capable of receiving a sensor strip and the device comprises:
- contacts;
- at least one display;
- and
- electrical circuitry establishing electrical communication between the contacts and the display, the circuitry comprising:
- an electric charger and a processor in electrical communication, the processor in electrical communication with a computer readable storage medium comprising computer readable software code, which when executed by the processor, causes the charger to implement an input signal comprising at least 3 duty cycles within 180 seconds between the contacts, each duty cycle comprising an excitation and a relaxation;
- where
- the input signal has a redox intensity of at least 0.01 if continued for a 10 second duration of the input signal;
- the processor is capable of measuring the output signal from an amperometric excitation of the at least 3 duty cycles, the amperometric excitation having a duration from 0.01 to 1.5 seconds, where
- the amperometric excitation follows a relaxation providing an independent diffusion and analyte reaction time during which the analyte generates measurable species;
- and
- the processor is capable of determining an analyte concentration of a sample from the measured output signal, where the determined concentration is responsive to a rate at which the measurable species is oxidized or reduced by the input signal.
-57. (canceled)
Dependencies are inferred from the claim text.