General metrological requirements of clinical lipid measurements.

Quantities in blood, plasma, or serum having lipid components are often difficult to define, especially as regards the component which must be selected according to chemical, biological, and clinical considerations. The choice of generic quantities and their respective measurement procedures relates to clinical requirements of allowable uncertainty, effectiveness, comparability, and compatibility determining goals of analytical reliability. The measurement procedure should define preanalytical requirements and be based upon traceability from tertiary and secondary reference materials with reference procedure values to primary reference materials. Such materials and procedures should be established internationally. A comprehensive quality assurance system of internal quality control and external quality assessment is essential to ensure worldwide and continued comparability. Validation and transferability should also be demonstrated by regional or international collaboration. Transmutation of results between procedures requires extensive investigations.