Enhanced Efficiency of PrepFiler™ BTA DNA Extraction Kit with PrepFiler™ Lysis Buffer Top-Up over Sample Remnants

The PrepFiler™ BTA Forensic DNA Extraction Kit (BTA) is designed to purify DNA from challenging forensic samples including tissue, bone, tooth and adhesive-containing substrates. Earlier versions of the manual state that lysates are stable at ambient temperature for 24 h when 300 µL of PrepFiler™ lysis buffer is added to the lysate. The effect of centrifuging additional PrepFiler™ lysis buffer over PrepFiler™ BTA-lysed remnants has not been evaluated previously. This study evaluated the DNA yield and STR profile quality of BTA lysates after 24 h with or without PrepFiler™ lysis buffer addition over sample remnants. Blood, semen and buccal cells on tape were processed with 300 µL of PrepFiler™ lysis buffer added directly to spun lysates (standard) or over sample remnants (top-up), and DNA extracted immediately or 24 h after lysis. The top-up method generated higher DNA yields for all tape samples tested, with diluted semen returning the greatest improvement. Comparison of standard and top-up methods for chewing gum, tissue and tooth samples showed that cigarette butt remnants must be removed prior to top-up to maintain resultant DNA quality. The top-up method maximizes DNA recovery using Prepfiler™ BTA, while enabling the combination of PrepFiler™ BTA and PrepFiler™ lysates DNA purification batches for high-throughput applications.