The fluidic system 10 of the preferred embodiment includes a sheath pump 12 to pump sheath fluid 14 from a sheath container 16 through a sample port 34 into an interrogation zone 18 and a waste pump 20 to pump the sheath fluid 14 and a sample fluid 26 as waste fluid 22 from the interrogation zone 18 into a waste container 24, and a processor 30 to calculate a time window based on the flow rate of the sample fluid 26. Preferably the processor 30 also calculates a time window for the sample fluid to reach the interrogation zone 18 from the sample port 34 based on the flow rate of the sample fluid 26. The interrogation zone 18 functions to provide a location for the fluidic system 10 and an optical analysis system 32 of the flow cytometer to cooperatively facilitate the analysis of the sample fluid 26.