Development and practical evaluation of an RT-PCR procedure using a real-time PCR instrument for saliva identification

Saliva is often left at crime scenes and its identification can prove useful in investigating criminal cases such as sexual assault. In this study, we developed a reverse-transcription polymerase chain reaction (RT-PCR) procedure for detection of STATH HTN3 markers characteristic saliva, using the QuantStudio 5 real-time PCR system (QS5). Discrimination criteria were then proposed evaluated on specificity, sensitivity, applicability to forensic casework. The assay performance QS5 was nearly identical that SmartCycler II (SCII), which has been discontinued. Our cutoff cycle quantification (Cq) values positive saliva Cq<40, 38, 40 ACTB, STATH, HTN3, respectively. ?Cq value also set 12. When applied, showed higher specificity compared with conventional presumptive or confirmatory tests. Detection sensitivity comparable SCII but lower than ?-amylase activity-based An evaluation made samples under various storage conditions mock casework samples. Unfortunately, results difficult obtain from stored long periods. Cq analyzed genes increased high humidity temperature conditions, although unchanged. contrast, significantly collected licked body surface, depending collection time. Positive obtained stains mixed 10 times volume other fluids, even though drastically changed. conclusion, RT-PCR suggesting potential effectiveness more precisely identifying when performed conjunction current confirmative