Abstract: The new method an products recognize human serum albumin, differentiating blood and tissue from human sources from blood and tissue of other animals. The method and products are particularly useful in forensic investigations. First, mice are injected with purified human serum albumin, spleen cells from the mice are fused with cells from a murine myeloma. Resulting hyberdomas are screened on human serum albumin coated plates. Subcloning, stabilizing by culture and continued assays for anti-human albumin activity produces products which recognize and differentiate blood or tissue samples from samples of other species.