ABC Forensic DNA case studies
ABC Forensic DNA · Put your knowledge to work in context.
The American Board of Criminalistics (ABC) describes certification as a voluntary process of peer review through which a practitioner is recognized as having attained the professional qualifications necessary to practice in one or more disciplines of criminalistics. Forensic DNA (DNA) is one of the ABC's certification examinations and one of the scopes listed under its accreditation ID 9106, alongside biological evidence screening, foundational knowledge, and seized drug analysis. The credential is aimed at working laboratory practitioners who perform forensic DNA analysis and want peer recognition of their knowledge, skills, and abilities. It is a professional distinction, not a license, conferred by a board whose directors represent regional and national forensic organizations. The ABC Forensic DNA case studies are 5 cases and about 3,137 words.
1Sperm-negative high vaginal swab with a strong PSA result
A 24-year-old woman reports an assault 96 hours earlier. The SANE collects a high vaginal swab, a cervical swab, and an external vulvar swab.
612 words, about 3 min2Degraded, inhibited bone extract: re-extract or amplify now?
A femur fragment recovered from a shallow grave is submitted for identification. The laboratory grinds 2 g of bone, demineralizes it, and extracts with a silica-based method, eluting in 50 µL.
608 words, about 3 min3Separating capillary electrophoresis artifacts from true alleles
A single-source bloodstain is amplified with a 24-locus STR kit and injected on a 3500-series capillary instrument at 15 s and 1.6 kV. The analyst observes the following.
652 words, about 3 min4Three-person mixture with a minor contributor below threshold
Tape from a handgun grip yields a mixture. Peak-height proportions are approximately 60%, 30%, and 5–8%.
635 words, about 3 min5Contamination signal in a 24-sample extraction batch
During a batch of 24 casework samples, the extraction negative control carried through the full procedure quantifies at 0.04 ng/µL. Its amplification shows D3S1358 allele 16 at 85 RFU, vWA allele 17 at 60 RFU, and D8S1179 allele 12 at 45 RFU.
630 words, about 3 min