Identification of aged bloodstains through mRNA profiling: Experiments results on selected markers of 30- and 50-year-old samples

•Bloodstains up to 53 years old can be identified through mRNA profiling.•HBA and HBB are proven the most stable mRNA markers for blood identification.•mRNA profiling has higher sensitivity and better durability than traditional methods.

Remarkable progress has been made in recent years on the research of body fluid identification through messenger RNA(mRNA) profiling. In order to examine the viability of mRNA profiling as a method to identify aged bloodstains, this study tested two groups of bloodstain samples, dated 30 years and 50 years back respectively, on seven blood specific markers, i.e. HBB, HBA, GYPA, CD93, ALAS2, SPTB (91 bp and 247 bp primers), and PBGD. Test results indicate that HBA and HBB are the most stable markers in aged bloodstains, returning positive results in over 80% of the 50-year-old samples and over 90% of the 30-year-old samples. This finding proves mRNA profiling an effective way of identifying aged bloodstains.