Concordance study between PowerPlex® ESI 16 Fast Kit and Investigator® 24plex GO! Kit

Short tandem repeat (STR) analysis is the cornerstone of forensic human identification due to its high discriminatory power and robustness. A concordance study was conducted to evaluate allele call consistency between two STR multiplex kits: PowerPlex® ESI 16 Fast (Promega Corporation, Madison, WI, USA) and Investigator®24plex GO! Kit (QIAGEN GmbH, Hilden, Germany). A total of 2000 buccal FTA cards (Whatman™ Flinders Technology Associates, Cytiva, Marlborough, MA, USA) samples previously typed with the PowerPlex® ESI 16 Fast Kit were re-analyzed using the Investigator® 24plex GO! Kit. An overall concordance rate of 99.982% was observed (59,989 concordant allele calls out of 60,000 total calls). Eleven discordant alleles were identified, including five cases of allelic dropout at distinct loci, five instances of allele shift (typically between D1S1656 and the adjacent DYS391), and one true mismatch at D1S1656. All discordances were confirmed by repeated amplification using both the PowerPlex® ESI 16 Fast and Investigator® 24plex GO! Kits, as well as the Investigator® 24plex QS Kit (QIAGEN GmbH, Hilden, Germany). The mismatch at D1S1656 was further confirmed by sequencing. The low discordance rate supports the reliability of the Investigator® 24plex GO! Kit for forensic reference databasing and enables a confident transition from the PowerPlex® ESI 16 Fast Kit.