ABFM Quality Control & Process Improvement 3 — Questions and Answers
Question 1: A forensic DNA laboratory's proficiency test result is reported as 'inconclusive' when the correct answer is a full inclusion. This error type is classified as:
- False positive
- False negative (Correct answer)
- Type I error
- Indeterminate error
Correct answer: False negative
Reporting 'inconclusive' instead of inclusion is a false negative because the correct association was missed.
Question 2: Which ISO/IEC 17025 clause specifically addresses the handling of nonconforming work in testing laboratories?
- Clause 6.4 (Equipment)
- Clause 7.10 (Nonconforming work) (Correct answer)
- Clause 8.3 (Internal audits)
- Clause 5.2 (Personnel)
Correct answer: Clause 7.10 (Nonconforming work)
ISO/IEC 17025:2017 Clause 7.10 requires laboratories to have a procedure for identifying, managing, and disposing of nonconforming work.
Question 3: In measurement uncertainty estimation, the 'Type B' evaluation of uncertainty is based on:
- Repeated measurements under the same conditions
- Information from calibration certificates, literature, or expert judgment (Correct answer)
- Inter-laboratory comparison results
- Gauge repeatability and reproducibility studies
Correct answer: Information from calibration certificates, literature, or expert judgment
Type B uncertainty uses non-statistical information such as manufacturer specifications, calibration data, or published reference values.
Question 4: A forensic laboratory implements a corrective action but the same nonconformance recurs six months later. The MOST likely root cause analysis failure was:
- Incorrect identification of the symptom
- Failure to address the true root cause (Correct answer)
- Excessive corrective action resources
- Inadequate proficiency testing frequency
Correct answer: Failure to address the true root cause
Recurrence of a nonconformance indicates the corrective action addressed symptoms rather than the underlying systemic root cause.
Question 5: Which tool visually displays the frequency distribution of data to reveal the shape of a process distribution?
- Run chart
- Scatter plot
- Histogram (Correct answer)
- Control chart
Correct answer: Histogram
A histogram groups data into intervals and displays the frequency of each interval, revealing distribution shape such as normality or skewness.
Question 6: In forensic pathology quality management, a 'sentinel event' is defined as:
- A routine variance in case turnaround time
- An unexpected occurrence involving death or serious harm requiring immediate investigation (Correct answer)
- A minor documentation error corrected before report sign-out
- A proficiency test result within acceptable limits
Correct answer: An unexpected occurrence involving death or serious harm requiring immediate investigation
Sentinel events are serious, unexpected adverse outcomes that trigger mandatory root cause analysis and system improvement.
Question 7: When performing a Gauge Repeatability and Reproducibility (Gauge R&R) study, 'reproducibility' measures variation due to:
- The same operator measuring the same part multiple times
- Different operators measuring the same part (Correct answer)
- Different instruments measuring different parts
- Different environmental conditions on the same instrument
Correct answer: Different operators measuring the same part
Reproducibility captures the variation introduced when different operators use the same measurement system on the same parts.
ABFM Quality Control & Process Improvement 3
A forensic DNA laboratory's proficiency test result is reported as 'inconclusive' when the correct answer is a full inclusion.
This error type is classified as: