Quality Control & Assurance in Testing Flashcards
7 cards from real CLT practice questions. Tap to flip, then mark Knew It or Still Learning — missed cards come back until you master them.
Read the first 7 Quality Control & Assurance in Testing flashcards as text
Which of the following is the MOST appropriate use of a blank (zero standard or reagent blank) in spectrophotometric analysis?
Answer: To set 100% transmittance and correct for reagent absorbance
The blank is used to zero the instrument, correcting for any absorbance contributed by the reagents themselves so only analyte absorbance is measured.
A laboratory participates in a College of American Pathologists (CAP) proficiency testing survey. The laboratory's result is flagged as unacceptable. According to CAP requirements, the laboratory MUST:
Answer: Investigate the cause and document corrective action within 30 days
CAP requires laboratories to investigate PT failures, identify root causes, implement corrective actions, and document the entire process, typically within 30 days.
A laboratory technologist notices that QC results for potassium have been slowly trending upward over 3 weeks without yet violating rejection rules. The BEST response is to:
Answer: Investigate the trend and recalibrate proactively before a rejection occurs
Trends indicate developing systematic error; proactive investigation and recalibration before a rejection rule is violated prevents reporting of erroneous patient results.
The FDA classifies laboratory tests into three categories. Which category requires the MOST regulatory oversight and includes most quantitative diagnostic tests?
Answer: Highly complex
Highly complex tests, which include most quantitative diagnostic assays, require the most personnel qualifications and quality control under CLIA/FDA regulations.
Six Sigma methodology is applied to a laboratory assay. A sigma value of 6 means the process produces approximately how many defects per million opportunities (DPMO)?
Answer: 3.4 DPMO
A Six Sigma process produces approximately 3.4 defects per million opportunities, representing near-perfect quality.
A laboratory performs linearity verification for a new troponin assay. Results at the high end of the range fall progressively below expected values. This MOST likely indicates:
Answer: Hook effect causing falsely low results at high concentrations
The hook effect in immunoassays occurs at very high analyte concentrations, where excess antigen saturates both capture and detection antibodies, causing falsely low results.
A laboratory implements a 'patient results QC' strategy using the average of normal patient results (anor method). This technique is MOST useful for detecting:
Answer: Slow systematic shifts affecting many patient results over time
The average of normals (Bull's algorithm for hematology; anor for chemistry) smooths individual variation, making it sensitive to slow systematic shifts affecting the population of patient results.