An automated analyzer for performing multiple diagnostic assays simultaneously includes multiple stations, or modules, in which discrete aspects of the assay are performed on fluid samples contained in reaction receptacles. The analyzer includes stations for automatically preparing a specimen sample, incubating the sample at prescribed temperatures for prescribed periods, performing an analyte isolation procedure, and ascertaining the presence of a target analyte. An automated receptacle transporting system moves the reaction receptacles from one station to the next. The analyzer further includes devices for carrying a plurality of specimen tubes and disposable pipette tips in a machine-accessible manner, a device for agitating containers of target capture reagents comprising suspensions of solid support material and for presenting the containers for machine access thereto, and a device for holding containers of reagents in a temperature controlled environment and presenting the containers for machine access thereto. A method for performing an automated diagnostic assay includes an automated process for isolating and amplifying a target analyte. The process is performed by automatically moving each of a plurality of reaction receptacles containing a solid support material and a fluid sample between stations for incubating the contents of the reaction receptacle and for separating the target analyte bound to the solid support from the fluid sample. An amplification reagent is added to the separated analyte after the analyte separation step and before a final incubation step.