The present invention provides a cartridge for analyzing a fluid sample. The cartridge provides for the efficient separation of cells or viruses in the sample from the remaining sample fluid, lysis of the cells or viruses to release the analyte (e.g., nucleic acid) therefrom, and optionally chemical reaction and/or detection of the analyte. The cartridge is useful in a variety of diagnostic, life science research, environmental, or forensic applications for determining the presence or absence of one or more analytes in a sample.