Forensic serology is the detection, classification and study of various bodily fluids such as blood, semen, fecal matter and perspiration, and their relationship to a crime scene. A forensic serologist may also be involved in DNA analysis and bloodstain pattern analysis.

Determination of the type and characteristics of blood, blood testing, bloodstain examination, and preparation of testimony or presentations at trial are the main job functions of a forensic serologist, who also analyzes semen, saliva, other body fluids and may or may not be involved with DNA typing. It must be recognized, however, that in many crime labs, there may be no clear distinction between job title and job function.