Abstract: A disposable liquid reagent cartridge for use with an analytical instrument includes a permanently closed hollow housing, a plurality of separate sealed flexible bags which are preformed independently of the housing and which are subject to damage and tampering if unprotected, at least some of the bags having reagents therein, the bags being supported in operative position within the housing, the housing being formed of the material sufficiently rigid to retain its outer shape and protect the bags supported therein from damage or tampering, connectors supported by the housing and being exposed to the exterior of the housing, and a flexible tube connected between each of the bags and the connectors to provide communication of the reagents between the bags and the connectors.