Quality Assurance and Quality Control Flashcards
8 cards from real Phlebotomy Test practice questions. Tap to flip, then mark Knew It or Still Learning — missed cards come back until you master them.
Read the first 8 Quality Assurance and Quality Control flashcards as text
The coefficient of variation (CV%) is calculated as:
Answer: (Standard Deviation ÷ Mean) × 100
CV% = (SD ÷ Mean) × 100; it expresses precision (reproducibility) as a percentage, allowing comparison across different analytes with different units.
In a laboratory with multiple analyzers running the same test, which QA practice ensures consistency of results across instruments?
Answer: Correlation studies comparing patient or QC results between instruments
Instrument correlation studies compare results from multiple analyzers to verify they produce equivalent results; significant differences must be investigated and resolved before using both instruments simultaneously.
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?
Answer: EDTA will be in excess relative to blood volume, causing cell shrinkage and altered CBC values
Underfilling an EDTA tube causes excess EDTA relative to blood volume, leading to osmotic shrinkage of red blood cells and falsely altered CBC parameters including decreased MCV and hematocrit.
Which document type in a laboratory quality management system describes step-by-step instructions for performing a specific procedure?
Answer: Standard operating procedure (SOP)
Standard operating procedures (SOPs) provide detailed, step-by-step instructions for performing specific laboratory procedures consistently and correctly.
The 'rule of four' regarding pre-analytical errors states that approximately how many laboratory errors occur in the pre-analytical phase?
Answer: 60–70% of all errors
Studies consistently show that 60–70% of all laboratory errors are pre-analytical, underscoring the critical importance of proper specimen collection and handling.
A laboratory monitors the number of specimen recollections due to clotted blood. This metric is BEST categorized as:
Answer: A pre-analytical quality indicator
Clotted specimens result from pre-analytical failures (inadequate mixing, delayed processing) occurring before laboratory analysis, making this a pre-analytical quality indicator.
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:
Answer: 3.4 defects per million
Six Sigma quality is defined as 3.4 defects per million opportunities, representing near-perfect performance and the highest achievable quality level in the Six Sigma framework.
After implementing corrective action for a QC failure, what step is REQUIRED before releasing patient results?
Answer: Run QC again to confirm the corrective action resolved the problem before releasing results
QC must be repeated after corrective action to verify the problem is resolved; only after passing QC can patient results be released—this is a fundamental principle of laboratory quality control.