Internal validation of two new retrotransposons-based kits (InnoQuant^® HY and InnoTyper^® 21) at a forensic lab

Obtaining a genetic profile from pieces of evidence collected at a crime scene is the primary objective of forensic laboratories. New procedures, methods, kits, software or equipment must be carefully evaluated and validated before its implementation. The constant development of new methodologies for DNA testing leads to a steady process of validation, which consists of demonstrating that the technology is robust, reproducible, and reliable throughout a defined range of conditions. The present work aims to internally validate two new retrotransposon-based kits (InnoQuant^® HY and InnoTyper^® 21), under the working conditions of the Laboratório de Polícia Científica da Polícia Judiciária (LPC-PJ). For the internal validation of InnoQuant^® HY and InnoTyper^® 21 sensitivity, repeatability, reproducibility, and mixture tests and a concordance study between these new kits and those currently in use at LPC-PJ (Quantifiler^® Duo and GlobalFiler™) were performed. The results obtained for sensitivity, repeatability, and reproducibility tests demonstrated that both InnoQuant^® HY and InnoTyper^® 21 are robust, reproducible, and reliable. The results of the concordance studies demonstrate that InnoQuant^® HY produced quantification results in nearly 29% more than Quantifiler^® Duo (indicating that this new kit is more effective in challenging samples), while the differences observed between InnoTyper^® 21 and GlobalFiler™ are not significant. Therefore, the utility of InnoTyper^® 21 has been proven, especially by the successful amplification of a greater number of complete genetic profiles (27 vs. 21). The results herein presented allowed the internal validation of both InnoQuant^® HY and InnoTyper^® 21, and their implementation in the LPC-PJ laboratory routine for the treatment of challenging samples.