Comparative performance of the Phadebas® Forensic Press Test at room temperature and 37 °C for the detection of saliva stains on fabric exhibits

Holly Woodford, Natasha Mitchell, Julianne Henry

Research output: Contribution to journalArticlepeer-review

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.

Original languageEnglish
Pages (from-to)170-174
Number of pages5
JournalScience and Justice
Volume61
Issue number2
DOIs
Publication statusPublished - Mar 2021

Keywords

  • Fabric exhibits
  • Incubation temperature
  • Phadebas Forensic Press Test
  • Phadebas Paper
  • Saliva
  • Sensitivity

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