Patent ID: 7593097

Claim:
A method for determining a test strip calibration code for use in a meter, the method comprising: inserting a test strip into the meter, the test strip having: a substrate, the substrate having: a working surface for receiving the body fluid sample; and a reverse surface that is in opposition to the working surface; and a permutative grey scale calibration pattern disposed on at least one of the working surface and reverse surface, the permutative grey scale calibration pattern including at least a first grey scale region and a second grey scale region, wherein the first and second grey scale regions define a grey scale permutation that uniquely corresponds to a calibration code of the test strip; detecting the permutative grey scale calibration pattern with a grey scale photodetector module of the meter; and determining a calibration code that uniquely corresponds to a grey scale permutation defined by the permutative grey scale calibration pattern based on a permutation matrix stored in the meter.