In-house validation of MPS-based methods in a forensic laboratory

Massively parallel sequencing (MPS) methods are increasingly applied in forensic casework. However, adequate validation guidelines are lacking. In this work, we describe our in-house validation of the ForenSeq DNA Signature Prep Kit (Verogen) for analysis of ancestry- and phenotype-informative SNPs. We also discuss in-house validation of MPS assays in general terms. When validating the SNP assay, we focused on the reliability of SNP genotype calls and the compatibility with commonly analysed sample types. Other issues, for example analytical thresholds and accuracy of the data prediction model were considered to be covered by the developmental validation of the kit. Our study included determination of (1) concordance, (2) limit of detection, (3) matrix effects, (4) repeatability, and (5) contamination risk. In conclusion, the MPS-based SNP assay showed overall adequate performance for single-source samples, with correct genotype calls. We welcome a broad discussion on how to perform in-house validation of MPS-based methods, as this is vital to ensure timely implementation of reliable assays in forensic laboratories.