This technical summary reports on a research project aimed at generating data in support of a reevaluation of the Federal Bureau of Investigation’s Quality Assurance Standard 9.4 and the 2018 Forensic Science Technology Working Group operational requirements.
This document reports on a study aimed at optimizing DNA evidence collection techniques, specifically direct polymerase chain reaction (PCR), that maximize DNA recovery from the collection of substrate and comprehensive studies that provide practical data about touch evidence. The goal of the project was to generate data in support of a reevaluation of the Federal Bureau of Investigation’s (FBI) Quality Assurance Standard (QAS) 9.4 and the 2018 Forensic Science Technology Working Group (TWG) operational requirements. This goal would be pursued by evaluating the following four items: direct PCR-compatible collection methods in conjunction with touch samples on a variety of substrates; direct PCR results from the GlobalFiler and PowerPlex Fusion 6C STR amplification systems; the efficacy of direct PCR when processing swabs that were stored after sample collection; and the efficacy of direct PCR on samples that were re-swabbed after initial analysis was completed. The project was performed in two phases: Phase I examined direct PCR-compatible collection methods in conjunction with mock touch DNA evidence samples on a variety of substrates; and Phase II examined direct PCR in conjunction with touch DNA samples that were collected using the optimum methods identified in Phase I and stored at room temperature for up to six months after collection. This document provides a detailed description of the methods used and the project results, which the authors suggest may aid the Scientific Working Group on DNA Analysis Methods (SWGDAM) in their reevaluation of QAS 9.4 by bolstering the argument for direct PCR of evidentiary samples and supporting modification of the guidelines requiring quantification. The results of this study may also lead to increased touch DNA profiling success rates, increased laboratory throughput and productivity, decreased turnaround times, and lowered processing costs.