System and method for analyte measurement

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.

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;   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;   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.   
     
     
         2 . The apparatus of  claim 1 , wherein the first signal comprises a signal having an AC component. 
     
     
         3 . The apparatus of  claim 2 , wherein the first signal comprises an AC signal. 
     
     
         4 . The apparatus of  claim 1 , wherein the biological fluid comprises blood. 
     
     
         5 . The apparatus of  claim 4 , wherein the medically significant component comprises glucose. 
     
     
         6 . The apparatus of  claim 5 , wherein the first correction value comprises an indicated glucose-to-actual glucose correction factor. 
     
     
         7 . The apparatus of  claim 1 , 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.   
     
     
         8 . The apparatus of  claim 7 , wherein the first signal comprises a signal having an AC component. 
     
     
         9 . The apparatus of  claim 8 , wherein the first signal comprises an AC signal. 
     
     
         10 . The apparatus of  claim 7 , wherein the biological fluid comprises blood. 
     
     
         11 . The apparatus of  claim 10 , wherein the medically significant component comprises glucose. 
     
     
         12 . The apparatus of  claim 11 , wherein the interferent comprises hematocrit. 
     
     
         13 . The apparatus of  claim 7 , wherein the first correction value comprises an indicated glucose-to-actual glucose correction factor.