Patent ID: 8182670

Claim:
A method for determining a concentration of a ketone in a sample, comprising the steps of: contacting a sample with a sensor, wherein the sensor comprises: a first electrode, a second electrode, and a third electrode; a sample chamber for holding the sample fluid, the sample chamber comprising the first electrode, the second electrode, and the third electrode, wherein the first electrode is positioned upstream of the second electrode relative to a sample entry port and the third electrode is positioned downstream of the second electrode relative to the sample entry port; and an ketone-responsive enzyme and a redox mediator disposed in the sample chamber; determining when the sample contacts the first electrode and the second electrode; determining when the sample contacts the first electrode and the third electrode; applying a potential between the first and second electrodes to electrolyze the ketone, thereby generating a ketone signal; and determining the concentration of the ketone using the ketone signal.