HT Quality Control & Assurance 3 — Questions and Answers
Question 1: Which proficiency testing program is most commonly used by US histology laboratories to satisfy CLIA requirements for nonwaived histopathology testing?
- American Proficiency Institute (API)
- College of American Pathologists (CAP) PT surveys (Correct answer)
- CDC Environmental Monitoring Program
- AABB Proficiency Testing
Correct answer: College of American Pathologists (CAP) PT surveys
CAP PT surveys are the most widely used approved proficiency testing program for histopathology in CLIA-regulated US laboratories.
Question 2: When validating a new antibody clone for immunohistochemistry, which tissue should be included as the positive control for Ki-67?
- Normal liver
- Tonsil germinal center (Correct answer)
- Resting skeletal muscle
- Adipose tissue
Correct answer: Tonsil germinal center
Tonsil germinal centers contain actively proliferating lymphocytes with high Ki-67 expression, making them ideal positive controls for this proliferation marker.
Question 3: A laboratory's Levey-Jennings chart shows the last 10 control values all falling on the same side of the mean but within 2s limits. Which Westgard rule is violated?
- 1â‚‚s warning rule
- 2â‚‚s rule
- 10â‚“ rule (Correct answer)
- Râ‚„s rule
Correct answer: 10â‚“ rule
The 10â‚“ rule is violated when 10 consecutive control values fall on the same side of the mean, indicating a systematic shift or drift in the process.
Question 4: What does a 'six-sigma' quality metric measure in a laboratory process?
- The number of reagent lots tested per year
- The process variation relative to acceptable limits, expressed as standard deviations (Correct answer)
- The percentage of slides with artifacts
- The frequency of equipment maintenance
Correct answer: The process variation relative to acceptable limits, expressed as standard deviations
Six Sigma measures how many standard deviations fit between the process mean and the nearest specification limit, with higher sigma indicating fewer defects.
Question 5: Which action is required when a CAP inspection reveals that a laboratory has no written policy for reagent expiration dates?
- No action needed if staining results are acceptable
- File a corrective action report and develop a written policy (Correct answer)
- Replace all reagents immediately regardless of date
- Transfer accreditation to another agency
Correct answer: File a corrective action report and develop a written policy
A deficiency found during CAP inspection requires a corrective action report detailing how the deficiency will be resolved, including creation of a written expiration-date policy.
Question 6: Which fixative artifact is most commonly detected during quality control review of lymph node biopsies?
- Retraction artifact from poor formalin penetration (Correct answer)
- Mercury pigment deposits from B-5 fixative
- Osmium blackening of lipid membranes
- Acid decalcification fracturing
Correct answer: Retraction artifact from poor formalin penetration
Inadequate formalin penetration in dense lymph nodes causes central artifactual 'retraction' or poor nuclear detail, detected during QC review.
Question 7: A laboratory logs that staining results failed QC and the run was repeated. Which document should record the root cause and action taken?
- Procedure manual
- Instrument maintenance log
- Corrective action log (Correct answer)
- Patient report form
Correct answer: Corrective action log
The corrective action log documents QC failures, their investigated root causes, and the steps taken to resolve and prevent recurrence.
HT Quality Control & Assurance 3
Which proficiency testing program is most commonly used by US histology laboratories to satisfy CLIA requirements for nonwaived histopathology testing?