Quality control of lipid measurements in epidemiological studies: the U.S. Air Force HEART program

A special standardization and quality assurance program, similar to that created for the Lipid Research Clinics Program (LRC), was developed for the American Health Foundation Laboratory by the Centers for Disease Control (CDC) to assure the quality of lipid measurements in the U.S. Air Force Health Evaluation and Risk Tabulation (HEART) Program. This study was designed to test the feasibility of reducing the incidence of heart disease in active-duty U.S. Air Force personnel through life-study intervention. During the 18-month study, CDC provided serum calibrators and reference materials for internal control and an external surveillance program for measurements of total cholesterol (TC) and high-density-lipoprotein cholesterol (HDLC). The Laboratory, using an automated enzymic method to measure cholesterol, achieved an overall goal for accuracy of less than 2% error (av systematic error, -30.6 mg/L) for TC, as measured on nine reference pools for which values were assigned by CDC. The average bias of measurements of HDLC with heparin-manganese to separate the lipoproteins in five CDC reference pools was -4.6 mg/L. Bias was estimated relative to the values assigned to the reference materials by the CDC reference methods for TC and HDLC. The average CV for TC was 0.89%, for HDLC 2.66%. Accuracy of cholesterol measurements can be assured over time with a standardization and quality-assurance program that incorporates accurately labeled reference materials for calibration, internal quality control, and external surveillance.