Abstract: A system and method for preparing a diagnostic fluid sample for use with a fluid assay system. The method comprises the steps of: amplifying the fluid sample to increase the number of cells subject to being tested; drawing a first volume of the fluid sample into a first syringe of a dual-barrel syringe and dispensing the first volume of the fluid sample through a media filter. The method further comprises the steps of placing the bacteria-laced filter into a lysis module; dispensing a first portion of a lysis buffer into the lysis module from the second syringe of the dual-barrel syringe; and dispensing a second portion of the lysis buffer through the media filter into a disposable cartridge of a fluid assay system.