Screening: as part of a regular health exam with a lipid panel when no risk factors for heart disease are present; once every four to six years in adults; youth should have a lipid panel 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 panel 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 is drawn from a vein in your arm. Sometimes a drop of blood is collected by puncturing the skin on a fingertip. This fingerstick sample is typically used when a lipid panel is being measured on a portable testing device, for example, at a health fair.
If this test is to be performed as part of a complete lipid panel, fasting for 9 to 12 hours typically will be required (drinking only water), but some healthcare practitioners allow non-fasting lipid panel testing. In particular, children, teens and young adults may have testing done without fasting. Follow any instructions you are given and tell the person drawing your blood whether you have fasted.
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 removal. HDL cholesterol is often called "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 and not enough is removed by HDL, it may be deposited in the walls of blood vessels. These deposits, called 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.
How is the test used?
The test for high-density lipoprotein cholesterol (HDL-C) is used as part of a lipid panel to screen for unhealthy levels of lipids and to determine your risk of developing heart disease and help make decisions about what treatment to use if you have borderline risk, intermediate risk, or high risk. The other components of a lipid panel typically include total cholesterol, LDL cholesterol (LDL-C), and triglycerides.
The results of the lipid panel are considered along with other known risk factors of heart disease to develop a plan of treatment and follow up. Depending on the results and other risk factors, treatment options may involve lifestyle changes such as diet, cessation of smoking or alcohol, and exercise or medications that lower lipid levels, typically statins.
As part of a lipid panel, HDL-C may also be used to monitor whether treatment has been effective in lowering cholesterol levels.
When is it ordered?
If you have risk factors or if previous testing showed that you had a high cholesterol level, more frequent testing with a full lipid panel is recommended. Major risk factors include:
- 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
Children, teens and young adults (ages 2 to 24 years old) with no risk factors should be tested at least once between the ages of 9 and 11 and once again between the ages of 17 and 21, according to the American Academy of Pediatrics.
Youths with an increased risk of heart disease as adults should have earlier and more frequent screening with lipid panels. Some of the risk factors are like those in adults and include a family history of heart disease or health problems such as diabetes, high blood pressure, or being overweight. High-risk children should have a fasting lipid panel between the ages of 2 and 8. Children younger than 2 years old are too young to be tested.
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.
What does the test result mean?
In general, healthy lipid levels help to maintain a healthy cardiovascular system and lower the risk of heart attack or stroke. Your healthcare practitioner will take into consideration the results of the HDL-C and the other components of a lipid panel as well as other risk factors to help determine your overall risk of heart disease, whether treatment is necessary and, if so, which treatment will best help to lower your risk of heart disease.
Health organizations have different recommendations for the treatment based on your predicted cardiovascular disease (CVD) risk (which is based on your age, weight, blood pressure, whether you smoke or have diabetes, and other factors).
If you are age 40 to 75 and do not have heart disease, current guidelines from the American College of Cardiology (ACC) and the American Heart Association (AHA) recommend that a risk calculator be used to determine your 10-year risk of CVD. Many factors are considered in the calculation, including total cholesterol, LDL-C, HDL-C, age, gender, race, blood pressure, diabetes, and smoking. The U.S. Preventive Services Task Force (USPSTF) makes similar recommendations. For more details, see the Lipid Panel article.
However, use of the risk calculator and ACC/AHA guidelines remain controversial and are evolving as more data become available. Many still use the older guidelines (2002) from the NCEP Adult Treatment Panel (ATP) III to evaluate HDL-C levels and heart disease risk as summarized below:
Low Level, Increased Risk Average Level, Average Risk High Level, Less than Average Risk Women Less than 50 mg/dL (1.3 mmol/L) 50-59 mg/dL (1.3-1.5 mmol/L) 60 mg/dL (1.55 mmol/L) or higher Men Less than 40 mg/dL (1.0 mmol/L) 40-50 mg/dL (1.0-1.3 mmol/L) 60 mg/dL (1.55 mmol/L) or higher
Note: Although high HDL-C is considered to be beneficial, a study published in 2018 by the European Society of Cardiology showed that very high levels of HDL cholesterol may also be associated with an increased risk of heart attack and death.
For children, teens and young adults:
Acceptable 45 mg/dL (1.17 mmol/L) or higher Borderline 40-45 mg/dL (1.04-1.17 mmol/L) Low Level, Increased Risk Less than 40 mg/dL (1.04 mmol/L)
My lab report includes a cholesterol ratio. What is it?
Some laboratories report a ratio of total cholesterol to HDL cholesterol (cholesterol ratio). The ratio is obtained by dividing the total cholesterol by the HDL cholesterol. For example, if you have 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.
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.
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 an increased risk of CAD. Further research is needed to determine what conditions contribute to an unexpectedly high risk of CAD in the presence of high HDL-C.
Is there anything else I should know?
HDL cholesterol should be measured when you are 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 delivery to have their HDL-C measured.