Prep-n-Go™: A new and fast extraction method for forensic blood samples

Forensics samples vary considerably in quality and quantity, making it particularly difficult to predict the amount of DNA available. Considering the entire procedure, one of the most important points is the extraction process (1). Such phase is absolutely decisive, since the higher the sample's handling, the greater the contamination probability. Prep-n-Go (TM) (ThermoFisher T Scientific, Foster City, USA) is an extraction buffer that enables high quality direct PCR amplification. This buffer allows a more secure extraction because it involves a limited handling of the sample, having only 2 steps -the buffer addition and the heating of the sample. On the other hand, Prep-nGo T is already validated for buccal swabs samples; however, one of the most common crime scene evidence is the blood sample. So, it was our purpose to validate this technique for swab blood samples extraction, by the evaluation of the quality of each obtained profile, through the observation of each allele height (in RFUs). Both extraction and amplification were performed with different volumes, in order to determine the best approach to be applied in the case of a forensic blood swab extraction with the referred buffer. For DNA amplification, we used different extract volumes, and the analysis of autosomal markers. We consider that our results show a new and essential strategy to perform a different and safer blood swab extraction, given the fact that this extraction reduces the samples manipulation.