Systems and methods of discriminating control solution from a physiological sample
Described herein are systems and methods for distinguishing between a control solution and a blood sample. In one aspect, the methods include using a test strip in which multiple current transients are measured by a meter electrically connected to an electrochemical test strip. The current transients are used to determine if a sample is a blood sample or a control solution based on at least two characteristics. Further described herein are methods for calculating a discrimination criteria based upon at least two characteristics. Still further described herein are system for distinguishing between blood samples and control solutions.
1. A method for calculating a discrimination criteria for programming into a test meter for distinguishing between a blood sample and a control solution sample, the method comprising the steps of:
(a) calculating an interferent index and a residual reaction index for a plurality of control solution samples in which the interferent index is based upon summing of at least two current values measured during a first test potential and the residual reaction index is based upon a ratio of at least two current values measured during a second test potential and third test potential, respectively; and
(b) calculating a discrimination criteria based on a regression of the interferent index and the residual reaction index for the plurality of control solution samples.
2. The method of claim 1 , wherein the discrimination criteria is a discrimination line.
3. The method of claim 2 , wherein the method further comprises the step of:
plotting an interferent index and a residual reaction index for a plurality of blood samples and shifting the discrimination line towards the plurality of blood samples.
4. A method for distinguishing between a blood sample and a control solution sample, the method comprising the steps of:
(a) introducing a sample into an electrochemical cell, the electrochemical cell comprising:
(i) two electrodes in a spaced apart relationship; and
(ii) a reagent;
(b) applying a first test potential, having a first polarity, between the electrodes, and measuring cell current;
(c) summing at least two current values measured during the first test potential to generate an interferent index;
(d) using the interferent index to distinguish between a blood sample and a control solution sample.
5. The method according to claim 4 , wherein the first potential is in the range of about 1 mV and 100 mV.
6. The method according to claim 1 , further comprising the steps of:
(e) applying a second test potential, having the first polarity, between the electrodes and measuring cell current;
(f) applying a third test potential, having a second polarity opposite of the first polarity between the electrodes and measuring cell current;
(g) determining a residual reaction index based on at least one current value measured during the second and third test potentials;
(h) using the residual reaction index to distinguish between a control sample and a blood sample.
7. The method according to claim 6 , in which residual reaction index is based on a ratio of at least one current value measured during the second test potential and at least one current value measured during the third test potential.