Screening a substrate for bodily fluids is an extremely important step for locating areas that may contain DNA. Several different methods have been developed for saliva (1). The Phadebas® Forensic Press (PFP) test is a presumptive saliva test that utilizes a preloaded paper that will react with the enzyme amylase, a component of saliva (2-5). Because of its ability to screen for amylase while simultaneously locating stains, the PFP may prove to be an effective, rapid method for screening. However it is important to assess whether the PFP introduces any inhibitors (7) to downstream processing such as PCR amplification. Based on previous studies, we hypothesize that the PFP will provide a rapid and sensitive method for locating multiple saliva stains simultaneously, without introducing inhibitors to DNA profiling. To test the limitations of PFP as well as evaluated its effects on DNA profiling we first created a dilution series of saliva ranging from neat to 1:5000. After this we preformed sensitivity tests on an indirect method, UV degraded samples and washed samples as well as with bodily fluid mixtures. Once all sensitivity tests were done, cuttings were taken from the substrate and PFP paper and analyzed for DNA. Tests found that the sensitivity ranges of the PFP were between 1:10 and 1:1000, indirect tests were less sensitive than direct, all bodily fluid mixtures were detected, and UV degraded samples took more time to react. In addition our DNA results confirmed our hypothesis that PFP does not inhibit DNA and is a useful method for locating stains. This project was funded by NSFREU Grant DBI 1262832.
Roda, Nicole; Lee, Steven B.; Barloewen, Brooke; and Mehmet, Tahnee
"DNA Typing Compatibility with a One Step Saliva Screening Test,"
Themis: Research Journal of Justice Studies and Forensic Science: Vol. 2
, Article 14.
Available at: http://scholarworks.sjsu.edu/themis/vol2/iss1/14