Successful mRNA profiling of 23 years old blood stains

In this study, 23 years old human blood stains on different and problematic carrier materials, such as jeans, leather, wood, wallpaper, carpet, wool, and nylon fabric, were investigated by mRNA analysis of the blood markers HBB and SPTB. HBB turned out to be a very stable marker that could be detected in all blood samples from all carrier materials whereas SPTB showed no positive result in any of these old samples. Typing of co-extracted genomic DNA provided full STR profiles with the exception of one stain resulting in a partial profile. No differences were observed regarding the quality of results due to possible inhibitorial substances from carrier materials such as jeans or leather, whereas some difficulties to extract nucleic acids were caused by the physical properties of materials such as carpet fibres. HBB can be highly recommended for the identification of old blood stains in forensic casework as it was possible to detect HBB even in stains that failed to provide a full DNA profile.