A flow cytometer is provided which includes an interrogation flow cell and a plurality of assay fluidic lines extending into the interrogation flow cell. A method of operating such a flow cytometer includes priming the interrogation flow cell with a sheath fluid and injecting different assay fluids into a flow of the sheath fluid through the plurality of fluidic lines. A fluidic line assembly is provided which includes a plurality of capillary tubes coupled to a base section configured for coupling to an interrogation flow cell assembly of a flow cytometer. The capillary tubes are dimensionally configured such that when the fluidic line assembly is arranged within the flow cytometer and fluid is dispensed from one or more of the capillary tubes at a given pressure differential with respect to an encompassing sheath fluid within the interrogation flow cell the fluid is substantially centrally aligned within the interrogation flow cell.