After a mass disaster, or in rural casework, human remains are often recovered where there is no refrigeration. Decomposition does not stop at collection, and every day of it costs DNA.

A study from Sam Houston State University, published in Forensic Science International: Genetics, tested two simple ways to collect and preserve decomposing human tissue in the field: a modified TENT preservative solution, and FTA Elute cards. Tissue was stored at room temperature for up to six months, then taken through several routes to an STR profile: a quick card lysis, silica-based purification, enzymatic extraction on the PDQeX, and simple dilution of the liquid preservative.

Both methods preserved relatively fresh tissue for the full six months. Decomposed tissue, collected between day 6 and day 14, was harder, and mostly produced partial profiles after storage. That is an honest finding and an important one: preservation slows the loss but does not reverse it.

Within that, two results stand out. The TENT preservative gave higher DNA concentrations and more successful STR results than the cards. And of the extraction approaches tested, the PDQeX generated the most successful STR typing results from decomposed tissue stored in TENT for six months at room temperature.

The authors also tested direct PCR, skipping extraction and quantification altogether, and found it comparable to the traditional pipeline. They recommend further work on direct approaches for casework-type samples.

For disaster victim identification planning, the practical point is that collection, preservation and extraction are worth designing together rather than one at a time.