ABFM Quality Control & Process Improvement 2 — Questions and Answers
Question 1: Which statistical tool uses upper and lower control limits to monitor process variation over time?
- Pareto chart
- Control chart (Shewhart chart) (Correct answer)
- Fishbone diagram
- Histogram
Correct answer: Control chart (Shewhart chart)
Control charts display process data over time with control limits to distinguish common-cause from special-cause variation.
Question 2: In forensic toxicology quality control, a 'matrix-matched' calibrator is used primarily to:
- Reduce reagent costs
- Compensate for matrix effects that alter analyte signal (Correct answer)
- Speed up batch processing
- Eliminate the need for internal standards
Correct answer: Compensate for matrix effects that alter analyte signal
Matrix-matched calibrators mimic the biological specimen matrix so that ion suppression or enhancement affects calibrators and samples equally.
Question 3: A Six Sigma project team is determining defect rates. Which metric expresses defects per million opportunities (DPMO)?
- Cp index
- Sigma level (Correct answer)
- Gauge R&R
- FMEA score
Correct answer: Sigma level
Sigma level is directly derived from DPMO; 6 Sigma corresponds to 3.4 DPMO.
Question 4: During a forensic autopsy laboratory audit, reviewers find that case files lack documentation of chain of custody for external specimens. This finding is BEST categorized as:
- Minor nonconformance
- Major nonconformance (Correct answer)
- Observation only
- Opportunity for improvement
Correct answer: Major nonconformance
Missing chain-of-custody documentation is a major nonconformance because it directly compromises specimen integrity and legal defensibility.
Question 5: Which lean principle focuses on producing only what is needed, when it is needed, in the amount needed?
- Poka-yoke
- Just-in-time (JIT) (Correct answer)
- 5S
- Value stream mapping
Correct answer: Just-in-time (JIT)
Just-in-time production minimizes inventory and waste by synchronizing production with demand.
Question 6: In a forensic laboratory, a second-source calibration standard is used primarily to verify:
- Instrument precision
- Accuracy of the primary calibration standard (Correct answer)
- Analyst competency
- Reagent shelf life
Correct answer: Accuracy of the primary calibration standard
A second-source standard from a different supplier or lot confirms the primary calibration standard is correctly prepared and uncontaminated.
Question 7: The PDCA cycle step in which root cause analysis and corrective actions are tested is:
- Plan
- Do (Correct answer)
- Check
- Act
Correct answer: Do
The 'Do' step involves implementing the planned changes or tests on a small scale to gather data.
ABFM Quality Control & Process Improvement 2
Which statistical tool uses upper and lower control limits to monitor process variation over time?