Phlebotomy Test Quality Assurance and Quality Control

Question 1

A Levey-Jennings chart plots control values over time against which reference points?

Accepted Answer

The mean and standard deviations (±1SD, ±2SD, ±3SD) of the control material

Answer

The patient's normal range for each analyte

Answer

The manufacturer's stated acceptable QC ranges

Answer

The previous day's QC values as a baseline

Question 2

Westgard's 1₃ₛ rule states that a QC run is rejected when:

Accepted Answer

One control value exceeds ±3SD

Answer

Two consecutive controls exceed ±2SD

Answer

The range between two controls exceeds 4SD

Answer

Ten consecutive controls fall on the same side of the mean

Question 3

A 'shift' in a Levey-Jennings chart is detected when:

Accepted Answer

Six or more consecutive control values fall on the same side of the mean

Answer

A single control value exceeds ±3SD

Answer

The control range (high minus low) exceeds 4SD

Answer

QC is not run for more than 24 hours

Question 4

What is the purpose of a 'delta check' in laboratory quality assurance?

Accepted Answer

To compare a patient's current result with their previous result to detect implausible changes

Answer

To verify the calibration of an analyzer before each run

Answer

To check the difference between high and low QC control values

Answer

To compare results from two different analyzers

Question 5

Which of the following is a PRE-ANALYTICAL error that can affect laboratory results?

Accepted Answer

Hemolyzed specimen due to difficult venipuncture

Answer

Analyzer malfunction during measurement

Answer

Incorrect reference range in the laboratory information system

Answer

Transcription error when entering results

Question 6

When a laboratory documents QC results, which of the following is the MINIMUM information that must be recorded?

Accepted Answer

Date, time, operator ID, lot numbers of controls and reagents, control values, and pass/fail decision

Answer

Only the final pass/fail decision

Answer

QC values and technologist name only

Answer

Control lot number and expiration date only

Question 7

The Westgard 10x̄ rule is used to detect which type of QC error?

Accepted Answer

Systematic error (bias)

Answer

Random error

Answer

Gross error

Answer

Precision error

Question 8

Turnaround time (TAT) monitoring is classified as which type of quality indicator?

Accepted Answer

Process quality indicator covering all phases

Answer

Pre-analytical quality indicator

Answer

Analytical quality indicator

Answer

Post-analytical quality indicator