CPC CPC Quality Assurance & Standards 2 — Questions and Answers
Question 1: Traceability of measurement results in a laboratory context means that results can be related to:
- The laboratory's internal calibration standards only
- A stated reference through an unbroken chain of calibrations with stated uncertainties (Correct answer)
- The manufacturing date of the instrument
- The analyst's personal calibration notebook
Correct answer: A stated reference through an unbroken chain of calibrations with stated uncertainties
Metrological traceability requires an unbroken chain of comparisons to higher-level standards (ultimately to SI units or accepted references) with stated uncertainties at each link.
Question 2: In Good Laboratory Practice (GLP), a study director is responsible for:
- Only conducting bench chemistry experiments
- Overall conduct of the study and ensuring the study protocol is followed (Correct answer)
- Maintaining laboratory equipment only
- Writing the final regulatory submission
Correct answer: Overall conduct of the study and ensuring the study protocol is followed
Under GLP regulations (FDA 21 CFR Part 58, EPA TSCA/FIFRA), the study director is the single point of study control, responsible for overall scientific conduct and protocol compliance.
Question 3: A laboratory's proficiency testing (PT) result is evaluated using a z-score. A z-score of |z| > 3 indicates:
- Satisfactory performance
- Questionable performance
- Unsatisfactory performance requiring corrective action (Correct answer)
- Excellent performance
Correct answer: Unsatisfactory performance requiring corrective action
In PT evaluation, |z| ≤ 2 is satisfactory, 2 < |z| ≤ 3 is a warning, and |z| > 3 is unsatisfactory, indicating the laboratory result is more than 3 assigned standard deviations from the consensus value.
Question 4: Under 21 CFR Part 11 (FDA), electronic records are acceptable if they include:
- Only the analyst's printed name
- Audit trails, access controls, and electronic signatures meeting specified requirements (Correct answer)
- Paper backup copies of all electronic data
- Only data from validated commercial software
Correct answer: Audit trails, access controls, and electronic signatures meeting specified requirements
21 CFR Part 11 requires electronic records to have audit trails capturing changes, controlled access, secure electronic signatures, and system validation to ensure authenticity and integrity.
Question 5: The purpose of running a method blank in environmental analysis is to:
- Determine instrument sensitivity
- Identify contamination introduced by the analytical process itself (Correct answer)
- Establish the calibration curve intercept
- Verify the spike recovery percentage
Correct answer: Identify contamination introduced by the analytical process itself
A method blank contains all reagents processed through the complete analytical procedure without the sample, detecting contamination from reagents, glassware, or laboratory environment.
Question 6: Recovery percentage in spiked sample analysis is calculated as:
- (Spiked result − unspiked result) / spike added × 100 (Correct answer)
- Spike added / (spiked result − unspiked result) × 100
- Unspiked result / spiked result × 100
- Spiked result / spike added × 100
Correct answer: (Spiked result − unspiked result) / spike added × 100
% Recovery = [(spiked result − unspiked result) / amount spiked] × 100, assessing how completely the method recovers the analyte from the sample matrix.
CPC CPC Quality Assurance & Standards 2
Traceability of measurement results in a laboratory context means that results can be related to: