High Density Lipoprotein (HDL)
|See Also||Lab Tests|
HDL, or High Density Lipoprotein, is composed mainly of phospholipids and apoproteins. It functions to transport cholesterol from the peripheral tissues and vessel walls back to the liver for processing and metabolism into bile salts. It is known as "good cholesterol" as the process of bringing cholesterol from the peripheral tissue to the liver protects against atherosclerosis. It also has the ability to influence the absorption and binding of LDL by smooth muscle and other cells, which provides protective benefits.,
- HDL is viewed in relation to the total cholesterol and the LDL cholesterol levels.
- HDL can be used as a strong independent diagnostic indicator to determine the risk for atherosclerotic coronary artery disease if the total cholesterol is high.
- Increased HDL is viewed as protective.
- Patient must fast 12 to 14 hours before testing. Water is permitted.
- Note: dietary indiscretion within the previous few weeks may influence lipoprotein levels.
- Factors which can cause increased levels
- Factors which can cause decreased levels
Ranges: The following are the reference ranges for this lab. However, lab ranges can vary by laboratory and country. 
|Standard U.S. Units||Standard International Units|
|Conventional Laboratory Range||40-90 mg/dL||1.03-2.32 mmol/L|
|Optimal Range||> 55 mg/dL||> 1.42 mmol/L|
|Alarm Ranges||< 35 mg/dL||< 0.91 mmol/L|
High levels indicate:
Low levels indicate:
- Hyperlipidemia and atherosclerosis
- Diets high in refined carbohydrates
- Syndrome X/hyperinsulinemia
- Oxidative stress
- Heavy metal/chemical overload
- Fatty liver (early developement) and liver congestion
- Lack of exercise or sedentary lifestyle
- Other conditions: obesity, Genetic predisposition, starvation, uremia
- Total cholesterol, LDL, triglycerides, apolipoprotein A and apolipoprotein B, blood glucose, lipid electrophoresis, homocysteine, oxidata free radical test, RBC, HCT, and HGB
- Pagana Kathleen D, Pagana Timothy J, (1998) Mosby's Manual of Diagnostic and Laboratory Tests, Mosby, Inc
- Weatherby Dicken, Ferguson Scott (2002) Blood Chemistry and CBC Analysis: Clinical Laboratory Testing from a Functional Perspective, Bear Mountain