As a qualitative serum with an optimized protein content to study the normal protein composition of hamster serum. To identify or quantitate a normal serum protein component using a variety of immunodiffusion techniques including immunoelectrophoresis, single and double radial immunodiffusion and electroimmuno-diffusion. As a reference serum in nephelometry and other auto-mated precipitation techniques. As a blocking agent or as a negative control in non-precipitating antibody-binding assays e.g. in serodiagnostic immunofluorescence and immunoenzyme tests. This normal reference serum does not contain assigned values for individual proteins but can be used as an internal relative standard for quantitative protein assays such as double radial immuno-diffusion (Mancini, Fahey), ELISA, Western immunoblotting and electroimmunodiffusion (Laurell), expressing the results obtained with the serum sample under investigation as a percentage of the protein concentration in the normal reference serum.