Forensic serology is the identification of bodily fluids, specifically blood, semen and saliva, on items of evidence related to a criminal investigation. The scientific concepts used in forensic serology are based on well established scientific principles, some dating back to the late 1800’s. For example in 1831, amylase activity was first noted in human saliva. In 1839, the first reliable procedures for the microscopic detection of sperm cells were published. Presumptive tests for blood based on hemoglobin oxidizing hydrogen peroxide were first described in 1863 and species precipitin tests, which allow for the detection of human blood, were developed in 1901.
In recent years, immunochromatographic tests employing the antigen-antibody reaction have begun to replace traditional electrophoresis/diffusion tests in the identification of blood and semen. Before the advent of DNA analysis, blood typing techniques were used for identification purposes, along with secretor status (the ability to secrete group antigens in body fluids other than blood.