Using the new Phadebas® Forensic Press test to find crime scene saliva stains suitable for DNA analysis

• The Phadebas® Forensic Press test is a new product that detects saliva stains by reacting with amylase. When the paper is pressed against a saliva stain a blue spot occurs. To test the sensitivity of the paper, a set of dilution series of saliva down to 1:500 was prepared on cotton fabric. Blue spots could be seen for dilutions of 1:100 when incubated at room temperature, and 1:200 in 37 °C. However, incubation at 37 °C did not provide acceptable reproducibility. The Phadebas® test was compared to four different lightsources for the ability to detect saliva on different carrier materials. Cotton fabric (T-shirt), denim, suede, leather, painted wood and untreated wood were tested. On denim, no stains could be detected with the lightsources, but Phadebas® showed all stains for pure saliva and dilution 1:5. DNA analysis was performed on detected stains and corresponding spots on the Phadebas® paper. Complete DNA profiles were produced for stains from pure saliva and dilution 1:5.

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