System and method for analyte measurement
View Patent ↗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.
1. An apparatus for determining the concentration of a medically significant component of a biological fluid, the apparatus comprising:
a cell for receiving a sample of the fluid, the cell supporting:
a chemistry which reacts with the medically significant component; and
first and second terminals across which the reaction of the chemistry with the medically significant component can be assessed;
wherein at least a portion of said chemistry is in contact with said first and second terminals;
an instrument having:
first and second terminals complementary to the first and second terminals, respectively, of the cell;
wherein placement of the first and second terminals of the cell in contact with the first and second terminals, respectively, of the instrument permits the instrument to assess the reaction; and
an assessment controller for:
applying across the first and second terminals of the instrument a first signal;
determining a first correction value in response of the cell to the first signal, wherein the determining a first correction value step comprises:
determining a frequency response of the cell to the first signal;
comparing the frequency response of the cell to a stored frequency response characteristic of a specific interferent to determine an interferent concentration; and
determining the first correction value based upon the interferent concentration;
assessing the reaction of the medically significant component with the chemistry; and
combining the correction value with the result of the reaction assessment to produce an indication of the concentration of the medically significant component of the sample;
wherein the first signal comprises a signal having an AC component.
2. The apparatus of claim 1 , wherein:
the biological fluid comprises blood;
the medically significant component comprises glucose; and
said chemistry comprises a chemistry which reacts with the glucose in the blood.
3. The apparatus of claim 2 , wherein the first correction value comprises an indicated glucose-to-actual glucose correction factor.
4. The apparatus of claim 1 , wherein the first signal comprises an AC signal.
5. The apparatus of claim 1 , wherein:
the biological fluid comprises blood;
the medically significant component comprises glucose;
the interferent comprises hematocrit; and
said chemistry comprises a chemistry which reacts with the glucose in the blood.
6. The apparatus of claim 5 , wherein the first correction value comprises an indicated glucose-to-actual glucose correction factor.