Analysis of rapid HIT application to touch DNA samples

Abstract

Rapid DNA technology is being utilized for reference profiles worldwide. There is also strong data in the literature to support its use for high‐template DNA sources, the same is not true for low‐template sources, such as touch DNA; this is a requirement before wider implementation to forensic casework is considered. We report on the Rapid HIT Intel cartridge's ability to facilitate successful amplification of touch DNA to obtain profiles from template deposited on items commonly encountered in forensic casework. Eight items were touched in ten replicates— two were tapelifted, three swabbed, and three directly inserted. Significance was observed in the alleles amplified and RFU with respect to sample type. Three samples performed well: cable tie, fabric, and matchstick. As two of these were directly inserted, this should be considered for any sample small enough. Placement of highly absorbent substrates into the cartridge is not advised as it can cause a lysate‐pull error. Heterozygote loci often presented as homozygous (32%–78% loci per profile); this was influenced by substrate type and profile RFU. Loci with larger masses exhibited higher false homozygosity also. Comparison of the donor's profile analyzed was performed against previous datasets analyzing touch DNA through standard workflow, including manual DNA extraction, PCR, and CE separation. These data show that for all substrates, except for a fabric swatch, standard processing is preferential to Rapid HIT analysis. In its current form, rapid DNA technology is not fit for the routine analysis of touch DNA samples in forensic casework.

A Systematic Review on Commercially Available Integrated Systems for Forensic DNA Analysis

“…However, it is known that rapid DNA techniques are less sensitive than conventional laboratory DNA analysis processes. This is caused by the conventional process having more sample work-up steps (i.e., extraction and/or purification) and using more sensitive machines [ 5 , 66 ]. Additionally, rapid DNA techniques are not or less suitable for resolving DNA mixtures [ 5 ].…”

“…The cable ties and matchsticks were directly placed into the cartridge of the RapidHIT. Together with tape-lifted fabric, these samples showed the best results [ 66 ].…”

Recent advances in forensic biology and forensic DNA typing: INTERPOL review 2019–2022

“…Some attempts to extend the range of sample types to low quantities of DNA or mixtures have been published with various levels of success (see Table 4 ). Researcher and practitioners from Australia [ [40] , [41] , [42] ], Canada [ 43 ], China [ 44 ], Italy [ 45 ], Japan [ 46 , 47 ], and the United States [ [48] , [49] , [50] , [51] , [52] , [53] , [54] , [55] , [56] , [57] ] have contributed to an increased understanding of rapid DNA testing capabilities and limitations.…”

Introducing a Rapid DNA Analysis Procedure for Crime Scene Samples Outside of the Laboratory—A Field Experiment

“…The RapidHit and RapidHit ID are retailed as equipment for fixed locations (e.g., booking stations))) DNA technologies, the ANDE, Rapid ID, and RapidHIT, are less sensitive and robust than DNA analysis performed via the regular procedures in laboratories [18,19]. Rapid techniques are therefore prone to produce incomplete results when low DNA concentrations are present [15,20] and they are less suitable for analyzing complex mixture profiles [21][22][23], which is the trade-off for the advantages of speed and mobility.…”