[Preliminary tests with Hemastix and Sangur test strips and Phosphatesmo KM test paper do not modify DNA typing of blood and semen stains].

Some of the commonly used presumptive test reagents for identification of blood and semen could affect the recovery or the analysis of high-molecular-weight DNA from evidentiary samples. The study presents data on restriction fragment length polymorphisms (RFLP) and polymerase chain reaction (PCR) analyses from blood and semen stains treated with Hemastix (Bayer Diagnostics), Sangur (Boehringer) and Phosphatesmo-KM-paper (Macherey-Nagel). The results demonstrate that the three tests examined do not have any effect on quality and quantity of the DNA nor on DNA typing by RFLP and PCR analyses. In conclusion, presumptive testing of blood and semen stains using Hemastix, Sangur, or Phosphatesmo paper can principally be carried out prior to submission to DNA analysis. In spite of these findings, it is recommended to continue the prudent practice of testing only small portions of an evidentiary stain in order to prevent contamination.