Active enzyme protection system for an electrochemical biosensor

A method of electrochemically analyzing an undiluted whole blood sample in a test sensor, the method comprising:

• introducing an undiluted whole blood sample to an inlet of a test sensor, the test sensor having at least one isolated flow path;
• contacting the undiluted whole blood sample with a lysing agent at a first chemical reaction zone in the at least one isolated flow path to release red blood cell constituents,
• then contacting the undiluted whole blood sample with an interference reduction matrix that reduces lysate interference,
• then contacting the undiluted whole blood sample with a proteolytic agent at a second chemical reaction zone in the at least one isolated flow path;
• then transferring the sample to a protease inactivation zone in the at least one isolated flow path;
• reducing the activity of the proteolytic agent by altering the chemistry of the sample at the protease inactivation zone;
• then transferring the sample from the protease inactivation zone to an electrochemical reaction zone in the at least one isolated flow path;
• then contacting the sample with an active enzyme that selectively undergoes a redox reaction with an analyte in the sample to produce a measurable species;
• and
• electrically altering the oxidation state of the measurable species with an electrode pair in response to an applied potential to generate an output signal component responsive to the analyte concentration of the sample.