DNA Efficiency Improvement with Rapid DNA

Abstract: With this award, the Hennepin County Sheriff’s Office - Forensic Science Laboratory will reduce case turnaround time by eliminating batch processing of reference samples and instead use rapid DNA technology for reference samples.  In our laboratory questioned samples must be completed before known reference samples. To accomplish the “questioned before known” requirement reference samples are added to a “knowns” batch as the questioned portion of the case is completed. To create a “knowns” batch with enough samples to make standard DNA testing efficient, the lab needs about two weeks of completed cases to accumulate enough reference samples (generally ~30 reference samples per batch). Completing the knowns batch requires approximately 14 hours of bench and instrument time and then another 2-3 hours for review and dissemination. When bench and review time is added to the time it takes for batch accumulation, the total time needed to complete a reference sample will vary from three to as many as 17 days. Cases that are completed at the beginning of the accumulation period will have the longest wait, while those completed near the end will have the shortest. In the case of known reference samples, batch processing actually increases the case completion cycle rather than shortening the time. 

We estimate that replacing batch processing with rapid DNA will save an average of 8 days on turnaround time for each case that requires reference sample processing.  The elimination of batch processing for reference samples will allow an analyst to run a reference sample and get results within 2 hours of completing the questioned evidence rather than waiting 3 – 17 days for a reference sample batch to be completed.

Continuing education and salary support for an existing Forensic Technician – DNA Screener is also part of this proposal.