The characteristics of seminal fluid and the forensic tests available to identify it

Abstract

Semen body fluid identification remains a critical aspect of the forensic investigation of alleged sexual assaults. Over the years, as advancements have been made in the area of forensic science, several different methods for semen identification have been utilized. It is not unusual for several methods of semen identification to be incorporated into a single sexual assault investigation. Most methods of semen identification are based on either detecting enzymatic activities or are targeted at specific cells or antigens. Other methods have evolved utilizing fluorescence or protein expression. Presumptive tests are often used to screen or locate semen staining. Further confirmatory tests can be used to identify the staining as semen and finally the donor of the stain can be further identified through DNA analysis. For routine application of these methods, they need to be specific, sensitive, cost effective, easy to use, and nondestructive. Although new techniques are being researched, it appears that traditional methods of semen identification remain the most widely applied in forensic casework. This article is categorized under: Forensic Biology > Body Fluid Identification

Recent advances in forensic biology and forensic DNA typing: INTERPOL review 2019–2022

“…A number of approaches are being taken to improve the sensitivity and specificity of BFID in recent years including DNA methylation [ [148] , [149] , [150] , [151] , [152] , [153] , [154] , [155] , [156] , [157] , [158] , [159] , [160] , [161] ], messenger RNA (mRNA) [ [162] , [163] , [164] , [165] , [166] ], microRNA (miRNA) [ 167 ], protein mass spectrometry for seminal fluid detection [ 168 ], and microbiome analysis [ 169 , 170 ]. Although many new techniques are being described in the scientific literature, traditional methods for semen identification are still widely used in regular forensic casework [ 171 ].…”

A Substitute Presumptive Test for Screening of Semen using Sodium –p– Nitrophenyl Phosphate (NaPNPP)

“…Over the years several different methods have been utilized for identi cation of seminal uid at a crime scene (Laffan et al 2011). Although new technologies are being researched and developed, traditional semen identi cation methods appear to remain the most widely applied in forensic casework (Gamblin and Morgan-Smith 2020). Of these methods acid phosphatase identi cation method still remains the most reliable and widely used presumptive test (Raju and Iyengar 1964;Rana et al 2019).…”

“…Quantitative and qualitative AP testing is routinely used in biochemical analysis and more importantly in screening for the presence of semen in evidence found at a crime scene. AP is one of the forensically signi cant components of semen and the activity of this enzyme is usually very high in seminal uids (Gamblin and Morgan-Smith 2020). The standard screening AP test for semen involves the use of alpha-naphthyl phosphate as a substrate to produce alpha-naphthanol in the presence of AP which then has to combine with Bretamine Fast Blue B (Orthodianisidine / diazo blue dye) to form a violet / purple coloured complex within 2 minutes (Raju and Iyengar 1964).…”