Species identification of blood and saliva stains by enzyme-linked immunoassay (ELISA) using monoclonal antibody.

An indirect enzyme-linked immunoassay (ELISA) method for the identification of human blood and saliva stains is reported. The method uses a monoclonal antibody which reacts with human immunoglobulin G (IgG) in extracts of blood and saliva stains up to 16 months old. Semen stain extracts gave weak or negative results. For routine screening purposes dilutions of 1:1000 for bloodstain extracts and 1:100 for saliva stain extracts would be suitable. Of 32 other animal species tested, only chimpanzee, mouse, rat, and eel cross-reacted significantly, and the presence of the last three was clearly indicated by appropriate controls. The monoclonal antibody gave poor results in the crossover and gel diffusion techniques.