Present Status of the Standardization of HDL-C, LDL-C, and TG Measurement Values Available in Japan

Abstract

Control sera used as evaluation samples in external quality control of HDL-C and LDL-C sometimes show disparities in results between direct methods differing in reaction principles. As a result, the present standardization status is unclear. In 2008, we investigated the present status of standardization of HDL-C, LDL-C, and TG measurement values available in Japan. To evaluate accuracy, refrigerated fresh human serum pools used as samples were analyzed irrespective of the manufacturer's method. To evaluate precision, a questionnaire survey regarding the internal quality control status at each institution was carried out. As evaluation criteria, the permissible limits of error of BA and CVA based on JSCC proposals, and the accuracy and imprecision criterion NCEP proposals were used. There were 70 participating institutions for HDL-C, 65 for LDL-C, and 71 for TG. TG values from the institutions showed 83.1-91.5% for both the JSCC BA range and the NCEP criterion range. HDL-C values within the JSCC BA range were 81.4-82.6% and within the NCEP criterion range the value was 98.6%. Similarly, LDL-C values within the JSCC BA range were 89.2% and within the NCEP criterion range the value were 81.5-83.1%, respectively. Concerning precision, a questionnaire regarding internal quality control of each institution was completed. More than 90% of the institutions showed values within the CVA range proposed by the JSCC for all of HDL-C, LDL-C, and TG. Standardization of lipid assays used for metabolic syndrome-based health checkups has been mostly achieved.