Measuring device and methods for use therewith

The equipment comprises a connector (93) for attachment of an electrochemical cell (39) having first and second electrodes and a reagent reactive with a constituent of human bodily fluid; a source of potential (34) external to the electrochemical cell; potentiometric circuitry (42) external to the electrochemical cell; electronic control means (54, 55) to controllably apply the source of potential to the electrochemical cell, thereby allowing current to flow through the cell; amperometric means (32) for measuring the flow of current through the electrochemical cell (39); the electronic control means coupled with the potentiometric circuit to automatically cease application of potential to the electrochemical cell, and then to measure a decay in chemical potential at the electrodes of the electrochemical cell in the absence of the applied potential.