Between the years of 2005 and 2010, the National Institute of Justice (NIJ) reserved $58 million to assist in the reduction of the arrestee and offender DNA backlog. Considering the limited resources available to forensic agencies, by relieving crime laboratories of the analysis of these reference samples this would allow for trained analysts to focus more of their efforts on crime related evidence. Rapid DNA (RDNA) systems, such as the RapidHIT® ID (IntegenX, Pleasanton, CA), can move the analysis of routine arrestee samples out of the lab and into booking stations. These RDNA systems would ideally be able to be operated by individuals with minimal training, most likely law enforcement personnel, and would require no further actions on their part other than inputting the necessary cartridge with preloaded reagents and the sample itself. To make certain that there is a successful RDIS upload, barcoding and RFID are utilized to track reagents and collected samples. The individual collecting the sample and the sample from the arrestee will be biometrically linked.
Written by: Rachel Wiley, University of North Texas Health Science Center with contributing authors Kelly Sage, Bruce Budowle, Bobby LaRue
Although the current RDNA platforms have proven to be reliable and robust in producing valid STR profiles, there are some limitations in the first generation RDNA systems that have been improved upon in the development of the RapidHIT ID platform. The current systems require 90 minutes from sample to profile, multiple samples must be run in tandem due to the design of the cartridges; and in utilizing complex cartridges, the cost per run is expensive. Ultimately, the RapidHIT® ID system addresses all of the aforementioned shortcomings. The RapidHIT® ID is able to complete a sample to profile run in approximately 60 minutes, runs a single sample at a time which is conducive to the needs of a booking station environment, and due to the incorporation of direct amplification, is approximately 25% less expensive in cost. In addition, with the RapidHIT® ID system’s ability to run a sample in roughly 60 minutes, this allows a favorable timeframe for repeat sampling if the initial run should fail for any reason. There are two chemistries commercially available for the RapidHIT® ID platform, GlobalFiler® Express (Thermo Fisher Scientific, Grand Island, NY) and NGM® (Thermo Fisher Scientific, Grand Island, NY).
In early 2015, Dr. Bobby L. LaRue of the University of North Texas Health Science Center (UNTHSC) in Fort Worth, TX was approached about collaborating on a project with IntegenX to perform an evaluation and validation of a new rapid DNA platform, the RapidHIT® ID. This collaboration allowed for a graduate student to travel to IntegenX in Pleasanton, CA to observe the research and development necessary to yield this second-generation rapid DNA system. This research internship granted UNTHSC early access to the instrument in order to conduct preliminary studies on the RapidHIT® ID platform.
In our comparative and concordance studies, genotypes were generated with GlobalFiler® utilizing traditional bench top methodology for concordance with those rendered on the RapidHIT® ID platform. Any observed points of discordance corresponded with allelic drop out resulting from sub-analytical threshold peaks that were present in the electropherograms, but were below cutoff values. The frequency of allelic drop out was similar between the two methods used for genotyping.
A contamination study was conducted incorporating an outline of alternating samples and blanks on a single instrument. The resulting electropherograms showed complete profiles for the sample runs and blank profiles for the blank samples suggesting that there was no carry over from run to run within the instrument.
In order to explore the RapidHIT® ID system’s reproducibility, a study was performed utilizing buccals from the same individual to develop genotypes on the RapidHIT® ID platform in sequential runs. To date, all samples from the same individual have yielded the same profile.
One major criticism of RDNA systems is sample consumption during analysis. To demonstrate the possibility of sample recovery and re-analysis in subsequent runs, a buccal swab was first genotyped on the RapidHIT® ID system utilizing a GlobalFiler® Express RapidHIT® ID cartridge. The same swab was removed and then re-analyzed during a second RapidHIT® ID run using a NGM® RapidHIT® ID cartridge. In addition, the re-analysis with NGM® chemistry addresses any concerns that amplified product may back flow and contaminate the original swab. Both analyses generated full profiles with no evidence of amplified product from the previous genotyping.
In conclusion, the RapidHIT® ID instrument was assessed for concordance, comparability with standard genotyping methods, evidence of contamination, reliability, and reproducibility. The sample size in this ongoing study is small, but preliminary results suggest that the RapidHIT® ID platform is able to genotype reference buccal swabs in approximately 60 minutes in a manner that is analogous to standard bench top methods. Moreover, in the event of a failed result, sufficient uncontaminated sample remains on the swab for swab recovery and re-analysis on either the RapidHIT® ID platform or by traditional bench top methods.
The presentation of this poster showing early access data accessing the functionality and influence of the RapidHIT® ID system in conjunction with the demonstration performed at the IntegenX booth by IntegenX CEO Robert Schueren at ISHI 26 appeared to greatly impact the audience. Many seemed to be intrigued by the capabilities of the RapidHIT® ID and support its aim to aid in the reduction of crime laboratory backlog through the processing of arrestee and offender reference sampling within booking stations. From a student perspective, being able to intern at IntegenX during the development of the RapidHIT® ID has been a memorable experience. Typically in the lab, we receive an instrument and evaluate it based on the final product; however, to be able to witness its evolution is something that I will always cherish.
Rachel Wiley is a Ph.D student of Molecular and Medical Genetics in Dr. Bruce Budowle’s lab at the University of North Texas Health Science Center in Fort Worth, TX. She has a Master of Forensic Science in Forensic Molecular Biology from The George Washington University in Washington, DC. During her time in Washington DC, she worked as the Forensic/ Cold Case Intern for the NCIS Washington DC Field Office. She is a Texas native. She earned her bachelors at the University of North Texas.
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