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)
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.
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