FDC Evidence Collection & Preservation 5 — Questions and Answers
Question 1: During a mass disaster response, the MOST critical reason to maintain separate collection teams for victim remains versus reference samples from family members is:
- Regulatory requirements mandate team specialization in mass fatality incidents
- To prevent cross-contamination that could lead to false kinship associations (Correct answer)
- Family members must be interviewed by separate personnel under victim protection laws
- Reference samples require a higher security clearance level for handlers
Correct 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.
Question 2: Which of the following would constitute a critical deviation requiring case documentation and supervisor notification under FBI QAS requirements during evidence examination?
- Use of a different brand of swab than specified in the standard operating procedure
- Discovery that a sealed evidence package contained an item not listed on the submission form (Correct answer)
- Performing DNA extraction in a different order than items are listed on the work sheet
- Finding that an item weighed 2 grams more than documented at submission
Correct 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.
Question 3: When using a presumptive test such as the Kastle-Meyer test in the field, a positive result means the analyst should:
- Confirm human origin by collecting the sample for species-specific serology (Correct answer)
- Collect the sample for DNA analysis, as the stain is confirmed as human blood
- Exclude the stain from further analysis if the color change is faint
- Proceed with DNA extraction immediately on-scene to preserve sample integrity
Correct 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.
Question 4: 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?
- 12 hours
- 72 hours (Correct answer)
- 5 days
- 7 days
Correct 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.
Question 5: To minimize analyst DNA contamination of evidence during extraction, laboratories require analysts to:
- Wear a single pair of nitrile gloves throughout all evidence handling
- Change gloves between each evidence item and avoid talking or coughing over open tubes (Correct answer)
- Work in a Class II biosafety cabinet at all times
- Submit a DNA profile to the laboratory staff elimination database voluntarily
Correct 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.
Question 6: A soil-contaminated skeletal remain found outdoors is BEST prepared for DNA analysis using which approach?
- Wash the bone with bleach solution to remove microbial contamination before sampling
- Decontaminate the bone surface mechanically with a Dremel tool, UV irradiate, then sample inner cortical bone powder (Correct answer)
- Soak the bone in proteinase K overnight before any surface decontamination
- Use PCR amplification directly on a surface swab without further decontamination
Correct 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.
Question 7: When a forensic laboratory receives evidence that lacks proper seals or tamper-evident tape, the CORRECT initial response under standard accreditation protocols is to:
- Accept and process the evidence with a notation that the packaging was compromised
- Refuse acceptance and return the evidence to the submitting agency immediately
- Accept the evidence and photograph the packaging deficiency, then notify the supervisor and submitting agency before proceeding (Correct answer)
- Process the evidence under expedited procedures to minimize further chain of custody gaps
Correct 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.
FDC Evidence Collection & Preservation 5
During a mass disaster response, the MOST critical reason to maintain separate collection teams for victim remains versus reference samples from family members is: