Abstract: An immunoassay kit for the qualitative and quantitative determination of a sample by the aid of specific binding partners such as, e.g., antibodies, antigens, receptors and ligands, includes a carrier or microtiter plate having a plurality of wells and precoated with a primary binding partner, which binding partner is present in fixed form as a lyophilisate. Part of the wells of the microtiter plate additionally contain a reference standard series of the sample to be determined with incremental dilutions in lyophilized form.