Westgard multirule for calculated laboratory tests.

Abstract

BACKGROUND: In clinical laboratories, many test results such as low-density lipoprotein (LDL)-cholesterol can be calculated using the results of specifically measured tests. However, quality control programs deal only with measured tests and there is no adequate quality assessment procedure for calculated tests. I aimed to apply the Westgard multirule to calculated tests as a part of routine quality procedures. METHODS: I prepared a Levey-Jennings chart for calculated tests and all their measured components (Equation chart) and then applied the Westgard multirule to these tests. RESULTS: Applying the Westgard multirule to calculated LDL-cholesterol (and other calculated tests) was simple, and increased the reliability of the results of the calculated tests. CONCLUSIONS: Checking the reliability of only measured tests by quality control procedures before reporting patient results may be inadequate. Applying the Westgard multirule to calculated tests as part of total quality management will increase the reliability of test results.