High-Density Lipoprotein (HDL) Cholesterol Test

What is the high-density lipoprotein (HDL) cholesterol test?

This is a blood test that measures a kind of fat (lipid) in the blood. This fat is called high-density lipoprotein (HDL) cholesterol.

Why is this test done?

The HDL test helps check your risk for heart disease or atherosclerosis, which is a hardening, narrowing, or blockage of the arteries.

HDL is also called good cholesterol. Having high levels of HDL in your blood reduces your risk of heart disease. (You can think of "H" for "healthy" cholesterol.) HDL attaches to and carries away harmful blood fats, such as low-density lipoprotein (LDL) cholesterol. LDL cholesterol is also called bad cholesterol (think of "L" for "lousy" cholesterol). HDL makes it harder for the LDL to stick to the walls of your blood vessels and cause disease.

Tests measuring LDL and other lipids, such as triglycerides, are often done at the same time as the HDL test. The higher your LDL, the greater your risk of having heart disease.

If you have changed your diet and exercise habits or are taking medicine to improve your cholesterol levels, this test can also help show how well your treatment is working.

How do I prepare for this test?

• It is generally recommended that you fast overnight before this blood test. For this reason, you should not eat or drink anything after midnight the night before your test. If you need to take medicines, you may take them with a small amount of water on the morning of your test.
• Lipid levels are affected by fat in your diet. Avoid eating fatty foods the evening before your test.
• Don't drink any alcohol for 24 hours before the test.
• Avoid exercise for 12 to 14 hours before the test.
• You may need to avoid taking certain medicines before the test because they might affect the test result. Make sure your healthcare provider knows about any medicines, herbs, or supplements that you are taking. Don't stop any of your regular medicines without first consulting with your healthcare provider.
• Talk to your healthcare provider before the day of your test if you have any questions about how to prepare.

How is the test done?

A small amount of blood is taken from your arm with a needle. The blood is collected in tubes and sent to a lab.

Having this test will take just a few minutes of your time. There is no risk of getting AIDS, hepatitis, or any other blood-borne disease from this test.

How will I get the test result?

Ask your healthcare provider when and how you will get the result of your test.

What does the test result mean?

Because HDL cholesterol protects against heart disease, higher numbers are better. A level under 40 mg/dL is low and is considered a major risk factor because it increases your risk for developing heart disease. HDL levels of 60 mg/dL or more help to lower your risk for heart disease.

Your HDL level may be low because:

• You smoke.
• You don't get enough exercise.
• You have an inherited tendency to have a low HDL.

What if my test result is low?

Test results are only one part of a larger picture that takes into account your personal and family medical history and your current health. Sometimes a test needs to be repeated to check the first result. Talk to your healthcare provider about your result and ask questions.

If your test result is not normal, ask your healthcare provider:

• if you need additional tests
• what you can do to work toward a normal value
• when you need to be tested again.