A system for conducting a plurality of different medical diagnostic tests comprises a hand-held portable self contained instrument for engaging a disposable test cell (308) containing a fluid to be tested. The instrument performs a diagnostic test selected from the plurality of tests upon the fluid within the test cell, the test being selected by the instrument based upon identification number obtained from the test cell. A disposable, single-use test cell is provided for receiving fluid to be diagnostically tested. The test cell includes identification information (101) indicative of a particular test to be performed upon the fluid, the test cell being sized and shaped for engagement by the instrument.
