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Medical Review - Articles by Medical Review Staff

Prepared March 1, 2006

Low Density Lipoprotein Cholesterol Testing

By Howell Johnson, M.D., Associate Medical Director

A fasting lipid profile is the recommended study for screening and for monitoring lipid lowering therapy.

The lipid profile consists of total cholesterol, HDL cholesterol, and triglycerides.  The LDL cholesterol is then calculated using the Friedewald formula: 

LDL = total cholesterol – HDL – (triglycerides)
                                                  5

The calculated LDL is considered accurate if the triglyceride level is less than 300 mg/dl.  When the triglyceride level is 300 or greater, the LDL cholesterol should be tested by direct measurement.

It is not medically necessary to routinely perform direct measurements of LDL cholesterol with triglyceride levels below 300 mg/dl.

References:

  1. Executive Summary of the Third Report of the National Cholesterol Education Program (NCEP) Expert Panel on Detection, Evaluation, and Treatment of High Blood Cholesterol in Adults (Adult Treatment Panel III).  JAMA 2001; 285:2486-97
  1. Piqnone MP, Phillips CJ, Atkins D, Teutsch SM, Mulrow CD, Lohr KN.  Screening and treating adults for lipid disorders.  Am J Prev Med. 2001; 20 (Suppl) :  78-89.

  2. Jacobs and DeMott:  Laboratory Test Handbook, 5th Edition, Lexi-Comp Inc. Cleveland, Ohio, 2001

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