title: Improved detection of semen by use of direct acid phosphatase testing.
abstract: Acid phosphatase (AP) reagent (Fast Black) is used as a presumptive test for the presence of seminal fluid on exhibits submitted in allegations of sexual assault. Research was carried out to determine whether the direct application of AP reagent to exhibits is a viable alternative to the traditional indirect (blot) testing method used routinely in the laboratory. The relative sensitivity of the indirect and direct testing methods was investigated as was the effect of AP reagent on histological staining of spermatozoa, the incidence of false positives from vaginal material and saliva, and the effect of AP reagent on subsequent DNA testing. Also included are the results of specificity studies from validations of the direct AP testing method. The results of this research show that, provided the incidence of false positives is borne in mind, direct AP testing can be especially useful when screening exhibits which are difficult to indirectly (blot) AP test or when it is problematic to relocate an AP positive stain. Direct application of AP reagent can also be beneficial for locating dilute semen stains. Three case examples are given which illustrate the use of direct AP testing in laboratory casework.
authors.affiliation: Cellmark Forensic Services, 16 Blacklands Way, Abingdon Business Park, Abingdon, Oxfordshire, OX14 1DY, United Kingdom. Electronic address: jlewis@cellmark.co.uk.
authors.forename: J
authors.initials: J
authors.lastname: Lewis
authors.forename: A
authors.initials: A
authors.lastname: Baird
authors.forename: C
authors.initials: C
authors.lastname: McAlister
authors.forename: A
authors.initials: A
authors.lastname: Siemieniuk
authors.forename: L
authors.initials: L
authors.lastname: Blackmore
authors.forename: B
authors.initials: B
authors.lastname: McCabe
authors.forename: P
authors.initials: P
authors.lastname: O'Rourke
authors.forename: R
authors.initials: R
authors.lastname: Parekh
authors.forename: E
authors.initials: E
authors.lastname: Watson
authors.forename: M
authors.initials: M
authors.lastname: Wheelhouse
authors.forename: N
authors.initials: N
authors.lastname: Wilson
mesh_terms: D000135:Acid Phosphatase / Q000032:analysis*; D004796:Clinical Enzyme Tests / Q000379:methods*; D016172:DNA Fingerprinting; D005260:Female; D006801:Humans; D007202:Indicators and Reagents; D008297:Male; D012661:Semen / Q000201:enzymology*; D012680:Sensitivity and Specificity; D013094:Spermatozoa / Q000201:enzymology
chemical_list: D007202:Indicators and Reagents; D000135:Acid Phosphatase
keywords: AP; Acid phosphatase; Body Fluid Forum; Direct; Semen; Testing