Inferring the presence of spermatozoa in forensic samples based on male DNA fractionation following differential extraction.

To address sexual assault kit backlogs some laboratories in North America have implemented 'Direct to DNA' (DTD) approaches for the examination of relevant vaginal, oral, rectal and external genitalia swabs from sexual assault examination kits. Using this approach no preliminary serological screening for semen or spermatozoa is performed. Instead, swabs are directly subjected to differential extraction and quantitation using a dual quantification system.