Quick Review Cards for Medical Laboratory Science

Quality Control Laboratory Operations Review 47

TERM EXPLANATION

Quality control (QC)

Control

External QC

Internal monitoring systems

Equivalent QC

Part of analytical phase of quality assurance; process of monitoring results from control samples to

verify accuracy of patient results.

Sample that is chemically & physically similar to unknown specimen & is tested in exactly the same

manner. Monitors precision of test system. For nonwaived quantitative tests, CLIA requires at least

2 levels of controls each day test is performed. (See “Equivalent QC” below.) For qualitative tests,

pos & neg controls must be included with each run.

Testing control material not built into test system. Term also used for QC that extends beyond lab,

e.g., participation in proficiency testing program.

Electronic, internal, or procedural controls that are built into test system.

Labs may reduce frequency of testing external QC materials for certain test systems if they can

demonstrate through a CMS-approved QC evaluation process that test system is stable.