Evidence Collection & Preservation Flashcards

During a mass disaster response, the MOST critical reason to maintain separate collection teams for victim remains versus reference samples from family members is:

Answer: To prevent cross-contamination that could lead to false kinship associations

If personnel or equipment contaminated with victim DNA also handle reference samples, spurious kinship matches could be produced, misidentifying remains.

Which of the following would constitute a critical deviation requiring case documentation and supervisor notification under FBI QAS requirements during evidence examination?

Answer: Discovery that a sealed evidence package contained an item not listed on the submission form

An unlisted item in a sealed package raises chain of custody concerns requiring documentation and notification before any analysis proceeds.

When using a presumptive test such as the Kastle-Meyer test in the field, a positive result means the analyst should:

Answer: Confirm human origin by collecting the sample for species-specific serology

Kastle-Meyer is a presumptive test for peroxidase activity that is not specific to blood or to humans, so a positive result warrants collection but not confirmation of blood origin.

A forensic nurse examiner using a sexual assault evidence collection kit must complete kit collection within what FDA-recommended time window post-assault to maximize DNA evidence yield?

Answer: 72 hours

National guidelines recommend completing sexual assault kit collection within 72 hours post-assault because biological evidence on external surfaces degrades and is lost rapidly beyond that window.

To minimize analyst DNA contamination of evidence during extraction, laboratories require analysts to:

Answer: Change gloves between each evidence item and avoid talking or coughing over open tubes

Glove changes between items prevent cross-contamination, and avoiding respiratory exposure over open samples prevents shedding of the analyst's own epithelial cells or saliva.

A soil-contaminated skeletal remain found outdoors is BEST prepared for DNA analysis using which approach?

Answer: Decontaminate the bone surface mechanically with a Dremel tool, UV irradiate, then sample inner cortical bone powder

Mechanical removal of the outer surface eliminates exogenous DNA, UV irradiation further degrades surface contamination, and sampling the inner cortical powder provides the best-preserved endogenous DNA.

When a forensic laboratory receives evidence that lacks proper seals or tamper-evident tape, the CORRECT initial response under standard accreditation protocols is to:

Answer: Accept the evidence and photograph the packaging deficiency, then notify the supervisor and submitting agency before proceeding

Accreditation standards require documentation of the packaging deficiency, photographic record, and notification prior to analysis so that all parties can assess admissibility implications.