PROBLEM TO BE SOLVED: To facilitate processing of a fluid sample according to different protocols using the same apparatus to determine the presence or absence of an analyte of the sample.SOLUTION: In a specific embodiment, a fluid control and processing system for controlling fluid flow among a plurality of chambers comprises a body including a fluid processing region coupled fluidically with a fluid displacement chamber 50. The fluid displacement chamber is depressurizable to draw fluid into the chamber and pressurizable to expel fluid from the chamber. The body includes a plurality of external ports 42, 46. The fluid sample processing region is fluidically coupled with at least two of the external ports. The fluid displacement chamber is fluidically coupled with at least one of the external ports. The body is adjustable with respect to at least the plurality of chambers to place one of the external ports in selective fluidic communication with the plurality of chambers.