Normal Sera

Normal serum is useful for blocking or as a negative control in immunoassays. Pre-incubation of immunoblots or tissue sections in buffer with 1-10% normal serum of the same species as the host of the conjugated antibody can reduce background due to nonspecific binding of the conjugate, and is sometimes more effective than albumin alone. Normal serum can also be used in assays as a negative control to measure background staining due to nonspecific binding or cross-reactivity, substituting for pre-immune serum if that is not available.