Normal Rat Serum, eBioscience?. Normal Sera are non-immune serum samples from goat, human, mouse, rabbit and other species that contain the usual complement of serum proteins, including the various classes of immunoglobulins that exist in healthy animals of the particular species. Normal serum provides a sufficient quantity of endogenous proteins to saturate and block nonspecific binding sites on fixed samples or assay substrates. When used as an antibody diluent, non-immune serum also supplies a native chemical environment for antibodies to function properly without adding foreign protein components. Normal serum is frequently used for blocking or saturating generalized binding interactions for immunodetection methods, especially tho