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2007, Volume 18, Number 1
By David F. Keren, M.D.
Warde Medical Laboratory recommends following the National Cholesterol Education Program (NCEP) Guidelines from 2001 that were updated in 2004 (1, 2). These guidelines recommend screening individuals for total cholesterol, low density lipoprotein (LDL) cholesterol, high density lipoprotein (HDL), and triglycerides on a fasting specimen. The guidelines themselves strongly emphasize the level of LDL cholesterol (LDL-C) as goals for individuals found to be at high risk for coronary heart disease.
NCEP recognized the following as major risk factors exclusive of LDL for coronary heart disease: cigarette smoking, hypertension (blood pressure >140/90 or on antihypertensive medication), low HDL (<40 mg/dl), family history of premature coronary heart disease (occurring in a male first degree relative before 55 years of age or in a female first degree relative before 65 years of age), age itself (men over 45 years, women over 55 years) and diabetes..
While some organizations endorse the use of LDL subfractions or particles to assess individuals for coronary heart disease, we have had concerns about the use of these measurements. Some of our concerns have been validated by a recent article from Ensign et al. in Clinical Chemistry (3). These authors directly compared on the same 40 samples four methods that are used to measure lipid subfractions: nuclear magnetic resonance (NMR), density gradient ultracentrifugation (VAP), gradient gel electrophoresis (GGE) and tube gel electrophoresis (TGE). Only 3 of the 40 samples (just 8%) showed complete agreement of the LDL pattern results out of these four methods. In an accompanying Clinical Chemistry editorial by Evan Stein, it was pointed out that just using triglyceride measurements with the NCEP adult treatment panel III cut-point of 150 mg/dl for triglycerides was as effective in predicting treatment pattern B or A as that provided by the subfraction data from the two methods that agreed most often (NMR and GGE) in the Ensign et al. study (4). The editorial concluded that use of the NCEP recommended triglyceride measurement was as helpful in predicting the LDL pattern as the costly LDL pattern measurements from the other, more costly measurements. Ensign et al. also report that the LDL-C concentration measurements from the 3 commercial laboratories showed surprising differences (4).
While the use of LDL and HDL subclasses may be of use in research investigations, at the present time, Warde Medical Laboratory continues its recommendation that clinicians follow the NCEP guidelines as modified in 2004 (1, 2).