Collection and storage of DVI samples with microFLOQ® Direct swabs for direct amplification

The rapid identification of decomposing human remains is a crucial component of disaster victim identification (DVI), often occurring in remote areas without access to laboratory or storage facilities. Due to the ease of collection and amenability to storage in harsh conditions, swabs may be used to collect DNA from decomposing remains as an alternative to sampling tissue or bone. Direct amplification could further streamline the process and reduce costs. This study investigated the efficacy of direct amplification of DVI samples using microFLOQ® Direct swabs and the QIAGEN Investigator QS GO! Kit. A comparison of performance between direct amplification and traditional methods was made to assess whether direct amplification offered an improvement to traditional methods. DNA was collected by swabbing the muscle of a decomposing human cadaver using three swab types (ADS Genetics 4N6FLOQSwabs®, NADS Genetics 4N6FLOQSwabs®, and the microFLOQ® Direct swab). Traditional swabs (4N6FLOQSwabs®) were extracted and quantified, while a direct amplification strategy was used with the microFLOQ® Direct swabs coupled with the Investigator 24Plex GO! Kit. Processing of the microFLOQ® Direct swabs were optimized and a hybrid strategy that used 4N6FLOQSwabs® to collect and store DNA before swabbing or "subsampling" the 4N6FLOQSwabs® for processing with microFLOQ® Direct swabs was developed. This hybrid strategy allowed for rapid processing without the consumption of the original sample. Traditional and direct PCR methods were comparable up to day 10 of decomposition depending on the sample location and for up to 3 months of storage at room temperature. This research indicated that microFLOQ® Direct swabs in conjunction with the Investigator 24Plex GO! Kit can be used to facilitate rapid direct processing of DNA from decomposing human remains.