Archived medical specimens as antemortem DNA references for disaster victim identification, optimization study following the October 7 massacre.

The October 7, 2023 terrorist attack in Israel resulted in over 1,200 casualties, creating unprecedented disaster victim identification (DVI) challenges. Traditional ante-mortem (AM) reference methods using personal items proved insufficient as entire families were affected. We implemented a novel strategy utilizing archived medical specimens from Ministry of Health repositories to construct a self-direct-reference antemortem (AM) DNA database. This study systematically evaluates factors affecting STR profiling success from 151 archived clinical specimens (2003-2023): histological samples (FFPE blocks/cytology slides, n = 131), diagnostic swabs (n = 8), and blood/serum (n = 12). Four variables were assessed: tissue source, extraction method, incubation protocol, and sample age. DNA was amplified using Investigator 24plex Kit, success measured by informative autosomal STR loci obtained (maximum 21). Descriptive and non-parametric inferential statistical analyses were applied to compare profiling outcomes across variable conditions, confirming statistically significant differences between sample types and methods. This study demonstrates that archived medical specimens represent reliable, viable and valuable sources of AM references with success rates ranging from 67 to 100% of mean locus recovery (proportion), depending on tissue type and processing optimization. The findings emphasize the potential of these specimens especially when traditional materials are unavailable and providing actionable guidance for global DVI preparedness.