Comparative analysis of two Rapid DNA technologies for the processing of blood and saliva-based samples

Abstract

Rapid DNA technologies recently gained significant momentum as a means to generate DNA profiles faster than with standard laboratory workflows. Initially developed for the analysis of buccal reference samples, applications are being considered for other types of forensic samples. In this study, an identical set of 150 blood and saliva-based samples was processed using two different Rapid DNA technologies, the Applied BioSystems™ RapidHIT™ ID System using the RapidINTEL™ sample cartridge and the ANDE™ 6C Rapid DNA Analysis™ System using the I-Chip. A subset of samples were subjected to alternative collection methods or sample pre-treatments to determine the optimal strategy for each instrument. An equivalent sample set was also processed using a conventional DNA analysis workflow. The sensitivity range of the two Rapid DNA technologies was comparable based on blood and saliva dilution series, with both technologies able to generate full profiles from samples typically yielding 5-10 ng of DNA when processed using conventional DNA analysis. The brand of cotton swabs used for Rapid DNA analysis had an impact on the results for both systems. Differences were observed in success rate between the two systems when processing blood (on fabrics, FTA paper or hard surfaces) and saliva-based samples (drink containers, FTA paper, chewing gum, cigarette butt filter paper) and depended on the sample type. Importantly, deviating from the manufacturer's instructions for sample collection and pre-treatment was more detrimental to the ANDE 6C results. The quality of DNA profiles, as assessed using heterozygote peak height ratios, interloci balance and artifact presence, confirmed the results to be reliable and acceptable for single source samples. Profiling results were obtained when samples were reprocessed using the same Rapid DNA technology or conventional DNA analysis. Secondary analysis using a substitute software (GeneMapper ID-X v1.5) to recover additional genetic information was shown to be feasible. Finally, a comparison between the Applied Biosystems™ RapidHIT™ ID System Software v1.3.1 and v1.3.2 was also performed. Findings of this study could assist those interested in using Rapid DNA technology for blood or saliva-based samples, in various settings and for different applications.

Keywords: ANDE 6C; Casework-type samples; DNA profiling; Rapid DNA analysis; RapidHIT ID; Sample collection; Success rate.