Advanced Lipoprotein Testing and Subfractionation Are Not (Yet) Ready for Routine Clinical Use

Abstract

Standard lipid tests measure the cholesterol or triglyceride content of lipoproteins, expressed as mg/dL (or mmol/L) of cholesterol or triglyceride. A standard lipid panel includes total cholesterol, low-density lipoprotein (LDL) cholesterol, high-density lipoprotein (HDL) cholesterol, and triglycerides. These lipids are carried within lipoprotein particles that are heterogeneous in size, density, charge, core lipid composition, specific apolipoproteins, and function.1 A variety of lipoprotein assays have been developed that subfractionate lipoprotein particles according to some of these properties such as size, density, or charge.2 These lipoprotein assays have been proposed for improving assessment of risk of cardiovascular disease (CVD) and for guiding lipid-lowering therapies. They are mostly used today in specialized lipid clinics or research studies, and their general utility for clinical practice is not well delineated.3 In this review, I first provide a summary of current guideline statements that address this topic. Then I give a brief overview of the different laboratory methods available for clinical use and discuss the literature evaluating these methods. Finally, I discuss current limitations to the widespread clinical application of these methods. Response by Superko on p 2404 The Third Adult Treatment Panel of the National Cholesterol Education Program4 and the American Heart Association5 recommend measuring a standard lipid panel in adults and targeting lipid-lowering therapy on the basis of levels of LDL cholesterol, and non-HDL cholesterol in subjects with hypertriglyceridemia. European and Canadian guidelines recommend measuring standard lipids while also emphasizing the total/HDL cholesterol ratio in risk assessment.6,7 Current guidelines do not recommend routine use of advanced lipoprotein tests, mainly because it is unclear how much incremental prognostic information is provided by these tests beyond that available from a standard lipid panel.4,6,7 Recently, an international panel proposed that cardiovascular risk may be more closely related to atherogenic lipoprotein …