An automated instrument for identification and/or characterization of a microbial agent present in a sample. The instrument includes (a) a sample removal apparatus operative to remove a test sample from a specimen container and add the test sample to a disposable separation device; (b) a separation and concentration apparatus operative on the separation device to separate the microbial agent from other components which may be present in the test sample and concentrate the microbial agent within the separation device; and (c) a identification and/or characterization module interrogating the concentrated microbial agent to identify and/or characterize the microbial agent.
