Gender-related difference in bloodstain RNA ratio stored under uncontrolled room conditions for 28 days

Bloodstain age is a parameter that can be used in crime scene investigations. Bloodstain age can be determined by measuring the 18S rRNA:β-actin mRNA ratio by Reverse Transcription-quantitative PCR (RT-qPCR). Since this ratio is a function of time, it can be used as an estimator of bloodstain age. However, it is important to validate the technique in a variety of scenarios before it can be applied. We investigated 18S rRNA:β-actin mRNA ratio in bloodstains from sixteen Chinese subjects in 28 days under uncontrolled room conditions. The ratio changed in a linear fashion. It was also found that the subjects' gender affected the relationship between time and the RNA ratio.