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
Which of the following is an example of a pre-analytical error that would affect QC and patient results?
Answer: Hemolyzed specimen due to improper venipuncture technique
Hemolysis caused by improper collection is a pre-analytical error that interferes with multiple analytes before the specimen even reaches the analyzer.
What is the primary function of an internal quality control (IQC) material compared to external proficiency testing (PT)?
Answer: IQC monitors day-to-day analytical performance; PT compares performance against peer laboratories
IQC monitors the consistency and accuracy of testing on a daily basis, while PT benchmarks a laboratory's performance against other labs using the same method.
A laboratory discovers that control results for a coagulation analyzer passed QC, but several patient PT/INR results appear unusually high. What should be done first?
Answer: Investigate a possible matrix effect or pre-analytical issue with patient samples
Passing QC does not rule out pre-analytical problems or matrix effects in patient specimens; clinical correlation and sample investigation are needed.
Which statistical measure best represents the day-to-day variability of a QC control material?
Answer: Coefficient of variation (CV)
The CV expresses standard deviation as a percentage of the mean, making it the best measure for comparing variability across different analytes or concentrations.
According to CLIA regulations, how long must a laboratory retain QC records?
Answer: 2 years
CLIA requires laboratories to retain QC records for a minimum of 2 years to allow review during inspections and accreditation surveys.
A laboratory is implementing a new hematology analyzer. Which validation study specifically confirms the analyzer produces equivalent results to the current method?
Answer: Method comparison study
A method comparison study tests patient samples on both analyzers simultaneously to confirm the new instrument produces clinically equivalent results.
Which of the following would cause a violation of the 2-2s Westgard rejection rule?
Answer: Two consecutive control values both exceeding +2s or both exceeding -2s
The 2-2s rule is violated when two consecutive QC values both exceed ±2 standard deviations on the same side of the mean, indicating systematic error.