Phlebotomy Test Quality Assurance and Quality Control 3

Question 1

The coefficient of variation (CV%) is calculated as:

Accepted Answer

(Standard Deviation ÷ Mean) × 100

Answer

(Mean ÷ Standard Deviation) × 100

Answer

(High QC − Low QC) ÷ Mean × 100

Answer

(Range ÷ Mean) × 100

Question 2

In a laboratory with multiple analyzers running the same test, which QA practice ensures consistency of results across instruments?

Accepted Answer

Correlation studies comparing patient or QC results between instruments

Answer

Running QC only on the primary analyzer

Answer

Using different reference ranges for each analyzer

Answer

Calibrating each analyzer with different calibrator lots

Question 3

A phlebotomist draws a sample in a lavender-top tube for CBC, but discovers the tube was only three-quarters full. What is the PRIMARY concern?

Accepted Answer

EDTA will be in excess relative to blood volume, causing cell shrinkage and altered CBC values

Answer

Insufficient blood volume may cause the analyzer to not recognize the sample

Answer

The sample cannot be centrifuged at the correct speed

Answer

The tube will not clot properly for the CBC

Question 4

Which document type in a laboratory quality management system describes step-by-step instructions for performing a specific procedure?

Accepted Answer

Standard operating procedure (SOP)

Answer

Quality policy

Answer

Quality manual

Answer

Control chart

Question 5

The 'rule of four' regarding pre-analytical errors states that approximately how many laboratory errors occur in the pre-analytical phase?

Accepted Answer

60–70% of all errors

Answer

40% of all errors

Answer

20% of all errors

Answer

Less than 10% of all errors

Question 6

A laboratory monitors the number of specimen recollections due to clotted blood. This metric is BEST categorized as:

Accepted Answer

A pre-analytical quality indicator

Answer

An analytical quality indicator

Answer

A post-analytical quality indicator

Answer

A calibration quality indicator

Question 7

Six Sigma methodology in a laboratory quality program uses 'defects per million opportunities' (DPMO). A process operating at Six Sigma quality has a DPMO of approximately:

Accepted Answer

3.4 defects per million

Answer

6,000 defects per million

Answer

66,800 defects per million

Answer

1,350 defects per million

Question 8

After implementing corrective action for a QC failure, what step is REQUIRED before releasing patient results?

Accepted Answer

Run QC again to confirm the corrective action resolved the problem before releasing results

Answer

Notify the medical director and wait for approval

Answer

Release results for specimens collected before the QC failure only

Answer

Document the corrective action and release all results on hold