Sci Justice. 2021 Mar;61(2):170-174. doi: 10.1016/j.scijus.2020.11.001. Epub 2020 Nov 21.
ABSTRACT
The Phadebas® Forensic Press Test (PFPT) is an enzyme-based colorimetric test used to visualise and locate latent saliva stains on forensic exhibits. The test relies upon the presence of the enzyme α-amylase which is present in high levels in saliva. Even though the optimal in vitro temperature for α-amylase activity is 37 °C, the PFPT manufacturer’s protocol specifies that the PFPT should be carried out at room temperature (RT). In this study, we compared the performance of the PFPT at RT and 37 °C using combinations of four fabric types (cotton, polyester, acrylic and a cotton/polyester blend), three saliva dilutions (neat, 1:10 and 1:100) and stains aged for four time periods (1 day, 1 week, 1 month and 3 months). The intensity of the PFPT colour reactions at RT and 37 °C were not statistically different across all fabric types, saliva concentrations and stain ages, indicating that maximum sensitivity and performance of the PFPT can be achieved at RT.
PMID:33736849 | DOI:10.1016/j.scijus.2020.11.001
