Wallach's Interpretation of Diagnostic Tests: Pathways to Arriving at a Clinical Diagnosis (810 page)

   Other Considerations

   The lipid profile does not measure LDL level directly but rather estimates it using the Friedewald equation:

   Note: The formula is only valid from a fasting specimen, and triglycerides must be <400 mg/dL.

   LDL-C can be measured directly when the triglycerides are elevated.

Suggested Reading

National Institutes of Health, National Heart Lung and Blood Institute’s National Cholesterol Education Program.
http://www.nhlbi.nih.gov/about/ncep/
. Accessed November 18, 2010.

CHOLESTEROL, TOTAL, SERUM

   Definition

   A steroid, carried in the bloodstream as a lipoprotein. It is necessary for cell membrane functioning and as a precursor to bile acids, progesterone, vitamin D, estrogens, glucocorticoids, and mineralocorticoids.

   
Normal range:
see Table 16.22.

TABLE 16–22. Initial Classification Based on Total Cholesterol and HDL Cholesterol

   Use

   Assessment of risk of heart disease and atherosclerosis

   Ordered in combination with HDL, LDL, and triglycerides as a lipid profile

   Interpretation