The Centers for Disease Control and Prevention (CDC) maintains a Lipid Standardization Program (LSP) that provides accuracy-based standards for measuring total cholesterol (TC), triglycerides (TG), high-density lipoprotein cholesterol (HDL-C), apolipoprotein A-I (apo A-I), and apolipoprotein B (apo B) in U.S. and international laboratories.

The LSP is unique among external quality-control systems (EQAS) in that it provides a way to establish, assess, and improve the accuracy—or trueness—of analytical measurements over time. The LSP provides traceability to CDC's reference measurement procedures (RMPs) for the measurement of TC, TG, and HDL-C. Traceability to designated comparison methods (DCMs) at Northwest Lipid Metabolism and Diabetes Reseraceh Laboratories (NWLMDRL) for apolipoproteins is provided through the LSP. In this way, the LSP standardizes the resulting measured values of these lipids, lipoproteins, and apolipoproteins no matter what analytical system is used. Measurement standardization ensures the credibility of results and valid comparability among different population studies and clinical trials. The CDC- LSP is not a proficiency testing (PT) program, in which performance assessment often is based on peer group means, not on traceability to accuracy standards.

To fulfill its commitment to improve the measurement of risk factors associated with cardiovascular disease, CDC focuses on two core activities:

• Maintaining a high-quality lipid reference measurement laboratory.
• Offering standardization services to domestic and international research laboratories.

CDC's assistance to research laboratories that measure lipids, lipoproteins, and apolipoproteins in clinical investigations and studies has had a major positive impact on the quality of analytical data produced. These studies continue to provide cardiovascular medicine with a reliable scientific database for evaluating risk factors associated with heart disease. For example, information from this database led scientists to the conclusion that elevated blood cholesterol is a significant risk factor in the development of heart disease and that lowering total cholesterol prevents or delays heart disease.

Participation in the LSP helps laboratories conducting lipid research, population studies, and related clinical trials for cardiovascular disease measure select lipids and lipoproteins with the levels of accuracy and precision needed to implement the recommendations by the National Cholesterol Education Program (NCEP). Laboratories that participate in the LSP's quarterly analytical evaluations and meet established performance standards receive a certificate of standardization from CDC to document this achievement.

There are currently no NCEP laboratory recommendations for apo A-I and apo B. The LSP provides information about bias to the DCMs and precision.