The decay factor, k, is defined as: k = ln ??? ( I r5 ) - ln ??? ( I r ??? ??? 10 ) ln ??? ( 10 ) - ln ??? ( 5 ) Eq . ??? 1 [0027] Note: k characterizes how the current decays in a general current-glucose relationship I=c???G???t???k, where I is the current, c is a constant, G is the glucose concentration, and t is the time. [0028] The Read-to-Burn ratio, R/B is defined as: R/B=I r10 /I b10???Eq.