What is Calibration Verification ?

Calibration Verification is a procedure where materials of known concentration are tested on an instrument in the same manner as actual patient specimens. This is a procedure used by laboratories to verify whether or not an instrument is accurately measuring samples throughout its entire reportable range.

What are Linearity Controls?

Linearity Controls are the specially engineered materials that laboratories require in order to perform actual calibration verification. These controls are expressly formulated with known concentrations of specific analytes that are in direct proportion to one another, and which are segmented into different ‘levels’. These levels are then run through an instrument in order to validate its calibration. After running a linearity control, technicians verify that the results given by an instrument are directly proportional to one another in the same manner as the individual ‘levels’ that were just run on the instrument.

Do All Laboratories Perform Calibration Verification?

Yes, or they will be performing it soon. According to the final clarification of Clinical Laboratory Improvement Amendments (CLIA), released in January 2003, any laboratory that carries out ‘moderately complex’ tests is required to perform calibration verification on their instrument. While laboratories were given a 2-Year cycle to ensure their compliance with these regulations, the rules outlined in CLIA will be fully enforced by the Centers for Medicare and Medicaid as of April 24, 2005.

How Often do Clinical Laboratories Performs Calibration Verification?

At least twice a year, for documentation purposes. But also whenever the following events occur:

• After any major preventative maintenance, or when critical parts affecting an instrument’s performance are replaced.
• After a laboratory switches lot numbers on the reagents it uses in conjunction with an instrument.
• After a laboratory identifies an unusual trend or shift reflected in its control materials, or results that fall outside of established acceptable limits.