Nonfasting vs. fasting cholesterol goals
What are the recommended goals for nonfasting cholesterol levels? Since we spend most of our life in a nonfasting state, shouldn't we be more concerned about nonfasting levels than we are about fasting ones?
—Bradley Hope, MD, Santa Barbara, Calif.
Since total serum cholesterol levels vary very little from the fasting to the nonfasting state, it is not necessary to obtain total serum cholesterol levels in the fasting state; the recommended goals for desirable levels are the same in each state. The reason fasting specimens are requested is because many clinicians want a lipid profile that also includes triglyceride levels and that measurement requires a fasting state. The reason to obtain triglyceride levels are twofold: (1) They are thought by some to carry a measure of atherogenic risk by themselves, especially in regard to the metabolic syndrome, and (2) they are used to calculate LDL levels according to the formula: LDL = total cholesterol - HDL - (triglycerides ÷ 5). Sometimes the triglyceride levels in a nonfasting specimen are too high to yield an accurate LDL calculation (Circulation. 2002;105:152-156).
—Peter F. Cohn, MD (117-21)