Type IV hyperlipidemia is characterized by abnormal elevations of VLDL, and triglyceride levels are almost always less than 1000 mg/dL. Type I hyperlipidemia is a rare disorder characterized by severe elevations in chylomicrons and extremely elevated triglyceride levels, always reaching well above 1000 mg/dL and not infrequently rising as high as 10,000 mg/dL or more. Type IIb hyperlipidemia is the classic mixed hyperlipidemia, with high cholesterol and triglyceride levels, caused by elevations in low-density lipoprotein (LDL) and VLDL. Type III hyperlipidemia or dysbetalipoproteinemia is characterized by an individual's decreased ability to convert VLDL and intermediate-density lipoprotein (IDL), a VLDL remnant, to LDL particles in the blood and because of a decreased clearance of chylomicron remnants. Type V is characterized by elevations of chylomicrons and VLDL; triglyceride levels are greater than 1000 mg/dL, and total cholesterol levels are always elevated.
The Endocrine Society recommends using fasting triglyceride levels over nonfasting triglyceride levels for the diagnosis of hypertriglyceridemia. Elevated triglyceride levels are determined by direct laboratory analysis of serum or plasma after a 10- to 12-hour fast. The following table lists triglyceride levels and their classification.
The National Cholesterol Education Program classified triglyceride levels as follows:
Normal: < 150 mg/dL
Borderline high: 150-199 mg/dL
High: 200-499 mg/dL
Very high: > 500 mg/dL
A standard lipid profile using the Friedewald equation to calculate the LDL cholesterol level is not useful if the triglyceride level is more than 400-500 mg/dL.
The Endocrine Society does not recommend routinely measuring lipoprotein particle heterogeneity in patients with hypertriglyceridemia, suggesting that although apolipoprotein B or lipoprotein(a) levels may be useful, results of other apolipoproteins are generally not clinically useful.
For more on the diagnosis and workup of hypertriglyceridemia, read here.
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Cite this: Romesh Khardori. Fast Five Quiz: How Much Do You Know About Hypertriglyceridemia? - Medscape - Sep 14, 2018.