A preliminary evaluation study of new generation multiplex STR kits comprising of the CODIS core loci and the European Standard Set loci.

The GlobalFiler™ (Life Technologies), Investigator® 24plex QS (Qiagen), and PowerPlex® Fusion 6C (Promega) kits are the latest generation 6-dye fluorescent chemistry STR-PCR amplification kits. These kits allow for the simultaneous amplification of the CODIS core loci and the European Standard Set loci, as well as a few Y-STR loci in addition to the standard sex-determining marker Amelogenin. The present study was designed to be a preliminary evaluation of the three STR-PCR kits in terms of sensitivity, profile recovery from degraded DNA samples, tolerance to PCR inhibitors, and detection of minor components in DNA mixtures. The results showed that the three STR-PCR kits had relatively similar performance with each kit faring better for the different aspects studied. The PowerPlex® Fusion 6C and the Investigator® 24plex QS kits were shown to tolerate inhibitors better, while the GlobalFiler™ kit appeared to have a higher mean percentage recovery of alleles from low template DNA samples and for minor components in DNA mixtures.

Evaluation of the RapidHIT™ 200 System: A comparative study of its performance with Maxwell(®) DNA IQ™/Identifiler(®) Plus/ABI 3500xL workflow.

RapidHIT(™) System is a rapid DNA instrument that is capable of processing forensic samples from extraction through to capillary electrophoresis and profile generation within two hours. Evaluation of the RapidHIT(™) 200 System was conducted to examine several key performance indicators of the instrument, including reproducibility, contamination, sensitivity, versatility and the possibility of sample re-extraction. Results indicated that the RapidHIT(™) 200 System was capable of generating high quality DNA profiles which were comparable to those from the standard protocol comprising of Maxwell(®) 16 DNA IQ(™) System, Identifiler(®) Plus and ABI 3500xL. No contamination was detected during the studies. Results also showed that the instrument was able to generate DNA profiles from samples containing lower amounts of DNA (0.5 µl of blood) albeit with more allele and locus dropouts when compared to the standard protocol. The ability to process blood swabs, blood-stained FTA punches, semen swabs, buccal swabs, product of conception (POC), bone marrow, fingernail clippings and cigarette butts at a good success rate indicated the robustness and versatility of the RapidHIT(™) 200 System. Furthermore, additional alleles could be recovered via re-analysis of the failed samples using the standard protocol. In summary, our results showed that the RapidHIT(™) 200 System was able to process casework samples for the purpose of providing rapid intelligence through DNA database searches and reference matching. Confirmative DNA results can be obtained through either concurrent processing of duplicate samples via standard protocol or re-extraction of samples retrieved from the RapidHIT(™) sample cartridge.