A disposable cartridge for mitigating cross-contamination of fluid sample reagents. The disposable cartridge includes a cartridge body defining a syringe barrel having an barrel port operative to inject and withdraw assay fluids in response to the displacement of a syringe plunger. Furthermore, the disposable cartridge includes a rotor defining a plurality of assay chambers in fluid communication with the barrel port through one of a plurality of rotor ports disposed about the periphery of the rotor. Finally, the disposable cartridge includes a flow control system between the barrel and rotor ports which prevents cross-contamination of fluid sample reagents from one assay chamber to another assay chamber.