RADIOIMMUNOASSAY OF TESTOSTERONE AND ESTROGENS IN BLOODSTAINS FOR THE PURPOSE OF SEX IDENTIFICATION

The capabilities and the limitations involved in applying commercially prepared Radioimmunoassay (RIA) Kits, for testosterone (T) and estrogen (E) , for the purpose of identifying the sexual origin of a bloodstain were examined. A total of forty whole blood samples were obtained from equal numbers of young healthy male and female volunteers. Bloodstains were prepared by absorbing these blood samples onto 2 X 2 cm squares of white cotton linen. Two separate studies were conducted using these stains. Both studies examined the fractional recovery of T and E when extracted with diethyl ether, the ability of the RIA method to detect T and E present in the extract at three bloodstain ages (2, 30, and 60 days after preparation) and whether a T:E ratio could be utilized as a basis for discriminating between male and female bloodstain samples. The difference between the studies lies in the prior knowledge of the sex of each individual blood sample. In the first study the sex of each blood sample was known, (open study), whereas in the second study the individual sex was not known but the number of each sex was known (single-blind study). A cross-reactivity study was performed to determine the direct interference of several commonly used synthetic steroids with the RIAs.