Quality Control & Assurance in Laboratory Practices Flashcards
7 cards from real CMLA 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 Laboratory Practices flashcards as text
When a control value falls outside the 2s warning limit but within the 3s rejection limit, which Westgard rule has been violated?
Answer: 1-2s warning rule
The 1-2s rule is a warning rule triggered when one control value exceeds ±2 standard deviations, signaling the need for increased scrutiny.
Which type of error causes all control values to shift consistently in the same direction from the mean?
Answer: Systematic error
Systematic error (bias) shifts results consistently in one direction, often due to reagent lot changes, calibration drift, or temperature issues.
A laboratory's Levey-Jennings chart shows the last six consecutive control values trending steadily upward. Which Westgard rule does this violate?
Answer: 10x rule
The 10x rule is violated when 10 consecutive control values fall on the same side of the mean, indicating systematic bias.
What is the primary purpose of running both normal and abnormal control levels in the laboratory?
Answer: To detect errors across the reportable range
Running controls at multiple levels ensures the method performs accurately across the entire clinically relevant range, not just at one concentration.
Which document defines acceptable performance specifications for a laboratory test, including allowable total error?
Answer: Method validation protocol
A method validation protocol defines performance specifications such as precision, accuracy, and allowable total error before a test is implemented.
If a laboratory's coefficient of variation (CV) for a glucose control is 3%, what does this indicate about the method's precision?
Answer: Acceptable precision for most routine chemistry tests
A CV of 3% for glucose is generally within acceptable limits for routine chemistry, indicating adequate but not perfect precision.
Which regulatory body sets proficiency testing (PT) requirements for laboratories under CLIA '88?
Answer: Centers for Medicare & Medicaid Services (CMS)
CMS administers the CLIA program and sets mandatory proficiency testing requirements for laboratories performing moderate- and high-complexity testing.