CMLA Quality Control & Assurance in Laboratory Practices 4

Question 1

Which of the following is an example of a pre-analytical error that would affect QC and patient results?

Accepted Answer

Hemolyzed specimen due to improper venipuncture technique

Answer

Hemolysis caused by improper collection is a pre-analytical error that interferes with multiple analytes before the specimen even reaches the analyzer.

Question 2

What is the primary function of an internal quality control (IQC) material compared to external proficiency testing (PT)?

Accepted Answer

IQC monitors day-to-day analytical performance; PT compares performance against peer laboratories

Answer

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.

Question 3

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?

Accepted Answer

Investigate a possible matrix effect or pre-analytical issue with patient samples

Answer

Passing QC does not rule out pre-analytical problems or matrix effects in patient specimens; clinical correlation and sample investigation are needed.

Question 4

Which statistical measure best represents the day-to-day variability of a QC control material?

Accepted Answer

Coefficient of variation (CV)

Answer

The CV expresses standard deviation as a percentage of the mean, making it the best measure for comparing variability across different analytes or concentrations.

Question 5

According to CLIA regulations, how long must a laboratory retain QC records?

Accepted Answer

2 years

Answer

CLIA requires laboratories to retain QC records for a minimum of 2 years to allow review during inspections and accreditation surveys.

(CMLA) Certified Medical Laboratory Assistant Practice Test

(CMLA) Certified Medical Laboratory Assistant Practice Test

CMLA Quality Control & Assurance in Laboratory Practices 4