The flow cytometer system of the preferred embodiment includes a flow cell body that functions to contain, protect, and align the components of the flow cytometer system; a flow channel, coupled to the flow cell body, that functions to conduct and focus sample fluid through an interrogation zone; and a sample injection probe, removably coupled to the flow cell body, that functions to provide a uniform flow of sample fluid to the flow channel. The flow cytometer system is preferably designed for the flow cytometer field. The flow cytometer system, however, may be alternatively used in any suitable environment and for any suitable reason.