Gated Voltammetry Methods
AssigneeBayer HealthCare LLC
InventorHuan-Ping Wu
Life of this patent
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Abstract
A sensor system, device, and methods for determining the concentration of an analyte in a sample is described. Gated voltammetric 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 pulse sequences may reduce analysis errors arising from the hematocrit effect, variance in cap-gap volumes, non-steady-state conditions, mediator background, a single set of calibration constants, under-fill, and changes in the active ionizing agent content of the sensor strip.
Claims26
A method of signaling a user to add additional sample to a sensor strip, the sensor strip including at least two electrodes, the method comprising:
- applying a gated voltammetric pulse sequence to the sample through the at least two electrodes of the sensor strip, the pulse sequence having at least two duty cycles,
- wherein each of the at least two duty cycles includes an excitation and a relaxation, and
- wherein the excitations of the at least two duty cycles include a potential varied with time and the relaxations of the at least two duty cycles include a current reduction to at least one-half the current flow at the excitation maxima;
- determining if the sensor strip is under-filled by comparing at least one current value recorded from the gated voltammetric pulse sequence including the at least two duty cycles to a pre-selected value;
- and
- signaling the user to add additional sample to the sensor strip if the sensor strip is under-filled.
A voltammetric method for determining a concentration of an analyte in a sample, the voltammetric method comprising:
- applying a pulse sequence to the sample, the pulse sequence comprising at least two duty cycles having excitation/relaxation time ratios from 0.3 to 0.2;
- measuring resulting currents from the at least two duty cycles;
- and
- determining the concentration of the analyte in the sample from the resulting currents.
A voltammetric method for determining a hematocrit concentration of a blood sample, the voltammetric method comprising:
- applying a gated voltammetric pulse sequence to the blood sample, the pulse sequence having at least two duty cycles,
- wherein each of the at least two duty cycles includes an excitation and a relaxation, and
- wherein the excitations of the at least two duty cycles include a potential varied with time and the relaxations of the at least two duty cycles include a current reduction to at least one-half the current flow at the excitation maxima;
- measuring resulting currents from at least one of the excitations;
- applying a semi-integral data treatment to the resulting currents, the semi-integral data treatment providing a peak portion;
- and
- quantitatively relating the peak portion to the hematocrit concentration of the blood sample.
-24. (canceled)
A voltammetric method for determining a percent hematocrit of a blood sample, the voltammetric method comprising:
- applying a gated voltammetric pulse sequence to the blood sample, the pulse sequence having at least two duty cycles,
- wherein each of the at least two duty cycles includes an excitation and a relaxation, and
- wherein the excitations of the at least two duty cycles include a potential varied with time and the relaxations of the at least two duty cycles include a current reduction to at least one-half the current flow at the excitation maxima;
- measuring resulting currents from at least one of the excitations;
- applying a derivative data treatment to the resulting currents, the derivative data treatment providing a negative derivative peak and a positive derivative peak;
- determining a ratio of the negative derivative peak to the positive derivative peak;
- and
- quantitatively relating the ratio to the percent hematocrit in the blood sample.
-30. (canceled)
A method of determining an amount of active ionizing agent available to react with an analyte, the method comprising:
- applying a gated voltammetric pulse sequence to a sample in a sensor strip through at least two electrodes, the pulse sequence having at least two duty cycles, the sample including an analyte and active ionizing agent,
- wherein each of the at least two duty cycles includes an excitation and a relaxation,
- wherein the excitations of the at least two duty cycles include a potential varied with time and the excitations include forward and reverse scans, and
- wherein the relaxations of the at least two duty cycles include a current reduction to at least one-half the current flow at the excitation maxima;
- measuring resulting currents from the forward and the reverse scans of at least one of the excitations;
- determining a ratio of the resulting currents from the forward and the reverse scans;
- comparing the determined ratio to a previously determined correlation ratio and a percent active ionizing agent;
- and
- determining the amount of the active ionizing agent available to react with the analyte.
-38. (canceled)
A method of determining a duration of a pulse sequence for determining the concentration of glucose in a blood sample, wherein the pulse sequence includes at least three duty cycles and each of the at least three duty cycles includes an excitation, the method comprising:
- determining a plurality of calibration sets from currents recorded during the at least three duty cycles;
- and
- determining the duration of the pulse sequence in response to a glucose concentration determined from the at least three duty cycles, wherein
- when the glucose concentration determined from the at least three duty cycles indicates a high glucose concentration,
- the duration of the pulse sequence is shorter than when the glucose concentration determined from the at least three duty cycles indicates a glucose concentration less than or equal to the high glucose concentration.
-45. (canceled)
Dependencies are inferred from the claim text.