A system for the electrochemical detection of analyte levels includes a test strip including an electrode and a counter electrode, the electrode and counter electrode located proximate to a sample reception area. The system further includes a coating on one of the electrode and counter electrode, the coating including a reagent coating for an analyte. The reagent coating includes a creatinine iminohydrolase, deamido NAD.sup.+, ATP, and NAD Synthetase/Mg.sup.2+.