CPC CPC Quality Assurance & Laboratory Procedures 2 — Questions and Answers
Question 1: What is the purpose of the laboratory's blind performance testing program under HHS certification requirements?
- To test the laboratory's accuracy by submitting unknown specimens that mimic real donor samples (Correct answer)
- To train collectors on proper specimen handling before collection begins
- To evaluate the MRO's ability to correctly interpret laboratory results
- To verify that the CCF is correctly completed before laboratory analysis begins
Correct answer: To test the laboratory's accuracy by submitting unknown specimens that mimic real donor samples
Blind performance testing involves submitting proficiency specimens to the laboratory as if they were real donor specimens, assessing the lab's accuracy without their knowledge.
Question 2: Which cutoff concentration must a urine specimen exceed on an immunoassay screen to be reported as a presumptive positive for marijuana metabolites?
- 50 ng/mL (Correct answer)
- 15 ng/mL
- 100 ng/mL
- 25 ng/mL
Correct answer: 50 ng/mL
The HHS-mandated initial immunoassay screen cutoff for marijuana metabolites (THC-COOH) is 50 ng/mL; specimens at or above this level proceed to GC-MS confirmation.
Question 3: What GC-MS confirmation cutoff concentration must be met or exceeded for a marijuana specimen to be reported as a confirmed positive?
- 15 ng/mL of THC-COOH (Correct answer)
- 50 ng/mL of THC-COOH
- 25 ng/mL of THC-COOH
- 10 ng/mL of THC-COOH
Correct answer: 15 ng/mL of THC-COOH
The GC-MS confirmation cutoff for THC-COOH is 15 ng/mL, which is lower than the initial screen cutoff, ensuring only true positives are confirmed.
Question 4: What does the laboratory report to the MRO when a specimen is positive on immunoassay but negative on GC-MS confirmation?
- A negative result (Correct answer)
- An invalid result
- A positive result with a notation
- A dilute negative result
Correct answer: A negative result
If the confirmatory GC-MS test does not meet the cutoff, the specimen is reported as negative, as the confirmatory result governs the final determination.
Question 5: Which professional is responsible for certifying each batch of test results at an NLCP-certified laboratory?
- A certifying scientist who reviews and signs off on each batch before results are reported (Correct answer)
- The laboratory director who reviews all results in monthly audits only
- The Medical Review Officer external to the laboratory
- Any laboratory technician authorized by OSHA
Correct answer: A certifying scientist who reviews and signs off on each batch before results are reported
A certifying scientist must review and certify each batch of drug test results before they are reported to the MRO, ensuring quality and accuracy at the laboratory level.
Question 6: What must the laboratory do if a specimen's primary vial (Bottle A) is accidentally broken before testing?
- The laboratory must notify the MRO, who may direct testing of the split specimen (Bottle B) (Correct answer)
- The laboratory must immediately collect a new specimen from the donor
- The laboratory must report the result as cancelled without notifying the MRO
- The laboratory must attempt to reconstitute the specimen from remaining fragments
Correct answer: The laboratory must notify the MRO, who may direct testing of the split specimen (Bottle B)
If Bottle A is unusable, the MRO can authorize testing of Bottle B under Part 40, preserving the ability to obtain a valid test result.
CPC CPC Quality Assurance & Laboratory Procedures 2
What is the purpose of the laboratory's blind performance testing program under HHS certification requirements?