CLC Laboratory Operations & Quality Management 2 — Questions and Answers
Question 1: A laboratory receives a proficiency testing (PT) sample that yields a Z-score of 3.2. What is the most appropriate immediate action?
- Report the result and take no action since Z-scores below 4.0 are acceptable
- Investigate potential root causes and implement corrective action before the next PT event (Correct answer)
- Discard the PT sample and request a replacement from the PT provider
- Suspend all patient testing until the PT failure is resolved
Correct answer: Investigate potential root causes and implement corrective action before the next PT event
A Z-score ≥2.0 is considered unsatisfactory and requires root cause investigation and documented corrective action.
Question 2: Which document control practice is required under ISO 15189 to prevent use of obsolete documents?
- Storing all previous document versions in an accessible archive
- Clearly marking superseded documents and removing them from points of use (Correct answer)
- Shredding all previous document versions immediately upon revision
- Requiring staff to memorize current procedures rather than referencing paper copies
Correct answer: Clearly marking superseded documents and removing them from points of use
ISO 15189 requires that obsolete documents be promptly removed from all points of use and clearly identified to prevent inadvertent use.
Question 3: A laboratory director reviews QC data and notices a Westgard 10x rule violation. This rule is triggered when:
- Ten consecutive control values fall on the same side of the mean (Correct answer)
- Ten QC results exceed 2 standard deviations in the same direction
- Ten consecutive runs show a progressive shift greater than 1 SD per run
- Ten different control levels all fail simultaneously
Correct answer: Ten consecutive control values fall on the same side of the mean
The 10x Westgard rule is violated when 10 consecutive control values fall on the same side of the mean, indicating systematic bias.
Question 4: Under CLIA '88, which of the following tests is classified as high complexity?
- Urine dipstick for glucose and protein
- Fasting plasma glucose using an FDA-cleared automated analyzer
- Gram stain interpretation of a clinical specimen (Correct answer)
- Home pregnancy test used in a physician office
Correct answer: Gram stain interpretation of a clinical specimen
Gram stain interpretation requires significant independent judgment and is classified as high complexity under CLIA '88 scoring criteria.
Question 5: A laboratory implements a new centrifuge. Which step is most critical before releasing patient results from this equipment?
- Performing a manufacturer-recommended preventive maintenance schedule
- Completing method verification studies to confirm performance specifications (Correct answer)
- Purchasing an extended warranty for the equipment
- Training all staff on the centrifuge operating manual
Correct answer: Completing method verification studies to confirm performance specifications
Method verification must be completed before any new instrument is placed into service to confirm it meets acceptable performance specifications.
Question 6: What is the primary purpose of an internal audit in a clinical laboratory quality management system?
- To identify staff performance problems for disciplinary action
- To evaluate whether the laboratory's processes conform to established requirements (Correct answer)
- To satisfy external accreditation body inspection requirements only
- To compare the laboratory's performance against competitor laboratories
Correct answer: To evaluate whether the laboratory's processes conform to established requirements
Internal audits systematically evaluate whether the laboratory's processes conform to its own defined requirements and identify opportunities for improvement.
Question 7: A specimen is received in the laboratory labeled only with a patient room number. According to best practices, what should the laboratory do?
- Process the specimen and add a note in the result report
- Reject the specimen and notify the ordering provider for proper recollection (Correct answer)
- Accept the specimen if the test is urgent and note the labeling deficiency
- Contact the nursing unit to verify the room number before processing
Correct answer: Reject the specimen and notify the ordering provider for proper recollection
Specimens lacking proper two-identifier patient labeling must be rejected and recollected to prevent patient identification errors.
CLC Laboratory Operations & Quality Management 2
A laboratory receives a proficiency testing (PT) sample that yields a Z-score of 3.2.
What is the most appropriate immediate action?