Patent ID: 7695600

Claim:
A test system comprising: (i) a capillary-fill biosensor for indicating electrochemically the catalytic activity of an enzyme in the presence of a fluid sample containing an analyte acted upon by said enzyme; the biosensor having a fluid inlet, a fluid outlet, and a capillary flow path connecting the fluid inlet and the fluid outlet; the biosensor further including a working electrode, a reference electrode and a counter electrode located within the capillary flow path; the working electrode including a catalytically-active quantity of said enzyme; wherein the reference electrode is separate from the counter electrode, and the reference and counter electrodes are arranged such that a fluid sample which flows evenly along the capillary flow path from said fluid inlet will substantially completely cover the reference electrode before the fluid sample makes contact with any part of the counter electrode; and (ii) a test meter for receiving said biosensor, the meter comprising: contacts for making electrical contact with each electrode on said biosensor; circuitry for performing an electrochemical measurement on said biosensor to produce a measured electrochemical value; circuitry for determining an analyte concentration value for a specified biological fluid from said measured electrochemical value; and circuitry for indicating a determined analyte concentration value; the meter further comprising: first signal circuitry for producing a first signal when an electrical circuit is detected between the reference electrode and the working electrode; second signal circuitry for producing a second signal when an electrical circuit is detected between the counter electrode and at least one of the reference electrode and the working electrode; a timer for determining the time interval between production of said first signal and said second signal; and a processor for triggering an error condition if said time interval exceeds a preset value or if said second signal is not produced within a preset time after said first signal is produced.