Also known as:HDL; HDL-C
Formal name:High-density Lipoprotein Cholesterol
Related tests:Cholesterol; LDL Cholesterol; Triglycerides; Lipid Profile; Cardiac Risk Assessment; Lp-PLA2
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Why Get Tested?
To determine your risk of developing heart disease
When to Get Tested?
Screening: as part of a regular health exam with a Lipid Profile when no risk factors for heart disease are present; once every four to six years in adults; children should have a lipid profile screening at least once between the ages of 9 and 11 and then again between the ages of 17 and 21.
Monitoring: may be done more frequently and at regular intervals as part of a lipid profile when risk factors for heart disease are present, when prior results showed high risk levels, and/or when undergoing treatment for unhealthy lipid levels
A blood sample drawn from a vein in your arm or from a fingerstick
Test Preparation Needed?
If this test is to be performed as part of a complete Lipid Profile, fasting for 9 to 12 hours typically will be required; only water is permitted. Your healthcare practitioner may decide that you may be tested without fasting. Follow any instructions you are given and tell the person drawing your blood whether or not you have fasted. For youths without risk factors, testing may be done without fasting.
How is it used?
The test for high-density lipoprotein cholesterol (HDL-C) is used as part of a lipid profile to screen for unhealthy levels of lipids and to determine an individual's risk of developing heart disease and to help make decisions about what treatment to use if there is borderline or high risk. The other components of a lipid profile typically include total cholesterol, LDL cholesterol (LDL-C), and triglycerides.
HDL-C is considered to be beneficial, the so-called "good" cholesterol, because it removes excess cholesterol from tissues and carries it to the liver for disposal.
As part of a lipid profile, HDL-C may also be used to monitor the effectiveness of treatment for unhealthy lipid levels. Treatment options may include lifestyle changes such as diet or exercise programs or lipid-lowering drugs such as statins.
When is it ordered?
HDL-C may be ordered as part of a Lipid Profile during a health checkup. It is recommended that all adults with no risk factors for heart disease be tested every four to six years.
As part of a lipid profile, HDL-C may be ordered as a follow-up test when someone has a high result on a cholesterol screening test.
HDL-C, as part of the lipid profile, may be ordered more frequently for those who have one or more risk factors for heart disease. Major risk factors include:
- Cigarette smoking
- Being overweight or obese
- Unhealthy diet
- Being physically inactive–not getting enough exercise
- Age (men 45 years or older or women 55 years or older)
- Hypertension (blood pressure of 140/90 or higher or taking high blood pressure medications)
- Family history of premature heart disease (heart disease in an immediate family member–male relative under age 55 or female relative under age 65)
- Pre-existing heart disease or already having had a heart attack
- Diabetes or prediabetes
Screening with a lipid profile is recommended for children as well as adults. Children should be tested at least once between the ages of 9 and 11 and once again between the ages of 17 and 21. As with adults, additional testing may be required for young people with other risk factors or if screening shows that levels are above the accepted levels. Some of the risk factors include a family history of heart disease or health problems such as diabetes, high blood pressure, or being overweight. Healthcare practitioners may order lipid profile screening for children under the age of 9 if a parent has high cholesterol, according to the American Academy of Pediatrics.
HDL-C levels may also be ordered at regular intervals to evaluate the success of lifestyle changes such as diet and exercise or smoking cessation aimed at increasing someone's level of HDL-C. Guidelines from the American College of Cardiology and the American Heart Association recommend that adults taking statins have a fasting lipid profile done 4 to 12 weeks after starting therapy and then every 3 to 12 months thereafter to assure that the drug is working.
What does the test result mean?
In general, healthy lipid levels help to maintain a healthy heart and lower the risk of heart attack or stroke. A healthcare practitioner will take into consideration the results of the HDL-C and the other components of a lipid profile as well as other risk factors to help determine a person's overall risk of heart disease, whether treatment is necessary and, if so, which treatment will best help to lower the person's risk.
In 2002, the National Cholesterol Education Program (NCEP) Adult Treatment Panel III provided guidelines for evaluating lipid levels and determining treatment. However, in 2013, the American College of Cardiology and the American Heart Association issued new guidelines for adults that made recommendations on who should receive cholesterol-lowing therapy. (For more details, see the Lipid Profile article).
However, use of the updated guidelines remains controversial. Many still use the older guidelines from the NCEP ATP III to evaluate lipid levels and CVD risk:
- If HDL-C is less than 40 mg/dL (1.0 mmol/L) for men and less than 50 mg/dL (1.3 mmol/L) for women, there is an increased risk of heart disease that is independent of other risk factors, including the LDL-C level.
- A typical level of HDL-C is between 40-50 mg/dL (1.0-1.3 mmol/L) for men and between 50-59 mg/dl (1.3-1.5 mmol/L) for women and is associated with average risk of heart disease.
- Based on many epidemiologic studies, HDL-C of 60 mg/dL (1.55 mmol/L) or higher is associated with a less than average risk of heart disease. The NCEP guidelines suggest that an HDL cholesterol value greater than 60 mg/dL is protective and should be treated as a negative risk factor. However, some recent studies suggest that high HDL-C is not universally protective (See Common Questions #2).
For children, teens and young adults:
- If HDL-C is less than 40 mg/dL (1.04 mmol/L), there is an increased risk of heart disease that is independent of other risk factors, including the LDL-C level.
- A level of HDL-C between 40 and 45 mg/dL (1.04-1.17 mmol/L) is borderline.
- A level of HDL-C greater than 45 mg/dL (1.17 mmol/L) is acceptable.
Some laboratories report a ratio of total cholesterol to HDL cholesterol. The ratio is obtained by dividing the total cholesterol by the HDL cholesterol. For example, if a person has a total cholesterol result of 200 mg/dL and an HDL cholesterol level of 50 mg/dL, the ratio would be stated as 4 (or 4:1). A desirable ratio is below 5 (5:1); the optimum ratio is 3.5 (3.5:1). The American Heart Association recommends that the absolute numbers for total blood cholesterol and HDL cholesterol levels be used because they are more useful than the ratio in determining appropriate treatment for patients.
Is there anything else I should know?
HDL cholesterol should be measured when a person is not ill. Cholesterol is temporarily low during acute illness, immediately following a heart attack, or during stress (like from surgery or an accident). You should wait at least six weeks after any illness to have cholesterol measured.
In women, HDL cholesterol may change during pregnancy. Women should wait at least six weeks after having a baby to have HDL-C measured.
What is being tested?
High-density lipoprotein (HDL cholesterol, HDL-C) is one of the classes of lipoproteins that carry cholesterol in the blood. HDL-C consists primarily of protein with a small amount of cholesterol. It is considered to be beneficial because it removes excess cholesterol from tissues and carries it to the liver for disposal. Hence, HDL cholesterol is often termed "good" cholesterol. The test for HDL cholesterol measures the amount of HDL-C in blood.
High levels of cholesterol have been shown to be associated with the development of hardening of the arteries (atherosclerosis) and heart disease. When cholesterol levels in the blood increase (not enough is removed by HDL), it may be deposited on the walls of blood vessels. These deposits, termed plaques, can build up, causing vessel walls to become more rigid, and may eventually narrow the openings of blood vessels, constricting the flow of blood. Photo source: NHLBI
A higher level of blood HDL-C is usually associated with a lower risk of developing plaques, lowering the risk of heart attack or stroke.
How is the sample collected for testing?
A blood sample is obtained by inserting a needle into a vein in the arm. Sometimes a drop of blood is collected by puncturing the skin on a fingertip. This fingerstick sample is typically used when HDL-C is being measured on a portable testing device, for example, at a health fair.
NOTE: If undergoing medical tests makes you or someone you care for anxious, embarrassed, or even difficult to manage, you might consider reading one or more of the following articles: Coping with Test Pain, Discomfort, and Anxiety, Tips on Blood Testing, Tips to Help Children through Their Medical Tests, and Tips to Help the Elderly through Their Medical Tests.
Another article, Follow That Sample, provides a glimpse at the collection and processing of a blood sample and throat culture.
Is any test preparation needed to ensure the quality of the sample?
Since this test is usually performed as part of a complete Lipid Profile, fasting for 9 to 12 hours before sample collection is typically required; only water is permitted. Your healthcare practitioner may decide that you may be tested without fasting. Follow any instructions you are given and tell the person drawing your blood whether or not you have fasted. For youths without risk factors, testing may be done without fasting.
- What treatments are recommended for low HDL-C levels?
Low HDL-C is not usually a target for treatment with medication. While some drugs used to lower LDL-C can also raise HDL-C, these drugs are not typically prescribed based on HDL-C levels. Certain lifestyle changes, however, may be recommended to help increase your HDL-C level. Since smoking can decrease HDL-C levels, quitting smoking (if you are a smoker) is a good way to increase HDL-C. Exercise is another good way to increase HDL-C. Alcohol consumption in moderation (1 to 2 drinks per day) has been reported to increase HDL-C, but there is some controversy about whether this is beneficial. Most physicians do not recommend increasing alcohol intake to increase HDL-C cholesterol.
- Can my HDL-C be too high?
High HDL-C has generally been found to be protective, decreasing the risk of coronary artery disease (CAD) in most people. However, some recent studies have shown that in some people with high HDL-C, the HDL-C is not protective and may, in fact, result in higher risk for CAD than in people with normal HDL-C levels. In one study, it was shown that people with CAD and high HDL-C had underlying genetic anomalies in enzymes important in lipid turnover (cholesterol ester transfer protein and hepatic triglyceride lipase). Another study showed that high levels of abnormally large HDL-C particles were associated with increased risk of CAD. Further research is needed to determine what conditions contribute to unexpectedly high risk of CAD in the presence of high HDL-C.
© 2017 American Association for Clinical Chemistry, republished from Lab Tests Online.*
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