Quality Assurance and Quality Control in the Clinical Laboratory

A set of vocabulary flashcards covering key concepts in quality management for the clinical laboratory, drawn from the lecture notes.

Quality

Overall standard of a process or product in the lab; expressed through accuracy, precision, and reproducibility.

Accuracy

Closeness of a measurement to the true value.

Precision

Repeatability or consistency of measurements; how close repeated results are to each other.

Reproducibility

Ability to obtain the same result across different operators, times, or equipment.

Documentation

Recording all steps and results; in the lab, if not documented, it did not happen.

Quality Assurance (QA)

Set of policies, procedures, and processes to ensure reliable and trustworthy results.

Quality Control (QC)

Operational checks using control materials to ensure analyzers and processes stay within acceptable limits.

Proficiency Testing

External, blinded samples sent by an agency to assess a lab’s competency and proficiency.

Pre-analytical Phase

All steps before analysis (patient ID, specimen collection, labeling, transport); errors often due to misidentification or mislabeling.

Analytical Phase

The actual testing on the analyzer, including pipetting, reagents, incubations, and instrument operation.

Post-analytical Phase

Reporting and interpretation of results; errors include failing to report critical values.

Control Material

A known-value sample used in QC to verify analyzer performance; typically multiple levels.

Calibration

Process of aligning an instrument’s measurements with known standards.

Trend

Gradual drift in QC results over multiple days.

Shift

Abrupt change in QC results to a new level.

Standard Deviation

A measure of dispersion/variability in a data set.

Coefficient of Variation (CV)

Standard deviation expressed as a percentage of the mean; lower CV indicates less variability.

Sensitivity

Ability of a test to detect the smallest amount of analyte; true-positive rate.

Specificity

Ability of a test to correctly identify those without the condition; true-negative rate; test is specific for the target analyte.

Gaussian Distribution

Bell-shaped curve; about 95% of values fall within ±2 SD, 99% within ±3 SD, 68% within ±1 SD.

Mean

Arithmetic average of a data set.

Median

Middle value of a sorted data set.

Mode

Most frequently occurring value in a data set.

Traceability

Ability to track every step of specimen handling and results, often via logs and LIS.

Signature Pages

Documents where personnel sign and initial to confirm handling of a specimen.

LIS (Laboratory Information System)

Digital system that tracks specimens, tests, and results.