Assay of "soluble fibrinogen" in bloodstain extracts as an aid to identification of menstrual blood in forensic science: preliminary findings.

Bloodstain saline extracts were prepared and “soluble fibrinogen” in the extract was measured by the hemagglutination inhibition technique. Total protein in the extract was also measured. Menstrual bloodstain extracts contained higher concentrations of “soluble fibrinogen” than did capillary bloodstain extracts. The two types of stain were better differentiated by calculating soluble fibrinogen as a percentage of the total protein in the extract. Extra#{243}tsof capillary blood plus semen stain, and of capillary blood plus vaginal secretion stain, contained higher proportions of soluble fibrinogen than did blood alone. The results are interpreted and their use for aiding the identification of menstrual bloodstains in forensic science is discussed.