A sample preparation device for preparing a sample according to an assay protocol, comprising: a plurality of support devices, each support device configured to support a plurality of assay devices; a cell deposition module operably engaged with the support devices and configured to deposit a sample on each of the plurality of assay devices supported by the support devices; an epitope retrieval module operably engaged with the support devices and the cell deposition module, and configured to deposit at least one reagent on each of the samples according to the assay protocol; a staining module operably engaged with the support devices, the cell deposition module, and the epitope retrieval module, the staining module being configured to deposit a staining reagent on each of the samples according to the assay protocol, and to remove excess staining reagent therefrom upon staining of the samples; and a plurality of heating source devices disposed in a heating module assembly on which the support devices are placed, each heating source device associated with a support device for heating the samples corresponding to each of the plurality of assay devices to a selected temperature, wherein each heating source device is operably engaged with the associated support device and has a biasing mechanism to bring the heating source device into uniform contact with the corresponding assay device by the assembly so as to heat each of the plurality of assay devices to the selected temperature in conjunction with the epitope retrieval module depositing the at least one reagent on each of the samples, according to the assay protocol, and wherein the staining module, the epitope retrieval module, and the cell deposition module cooperate with the support devices to form a unitary sample preparation device for preparing the sample without movement of the assay devices with the support devices. a plurality of support devices, each support device configured to support a plurality of assay devices; a cell deposition module operably engaged with the support devices and configured to deposit a sample on each of the plurality of assay devices supported by the support devices; an epitope retrieval module operably engaged with the support devices and the cell deposition module, and configured to deposit at least one reagent on each of the samples according to the assay protocol; a staining module operably engaged with the support devices, the cell deposition module, and the epitope retrieval module, the staining module being configured to deposit a staining reagent on each of the samples according to the assay protocol, and to remove excess staining reagent therefrom upon staining of the samples; and a plurality of heating source devices disposed in a heating module assembly on which the support devices are placed, each heating source device associated with a support device for heating the samples corresponding to each of the plurality of assay devices to a selected temperature, wherein each heating source device is operably engaged with the associated support device and has a biasing mechanism to bring the heating source device into uniform contact with the corresponding assay device by the assembly so as to heat each of the plurality of assay devices to the selected temperature in conjunction with the epitope retrieval module depositing the at least one reagent on each of the samples, according to the assay protocol, and wherein the staining module, the epitope retrieval module, and the cell deposition module cooperate with the support devices to form a unitary sample preparation device for preparing the sample without movement of the assay devices with the support devices.