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 called good cholesterol because 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 other lipids, such as low-density lipoprotein (LDL). 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. Dividing your LDL level by your HDL level gives a number called the LDL/HDL ratio. It is good to have a ratio of 3 to 1 or lower.

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.
• Many lipid levels are affected by fat in your diet. Avoid eating fatty foods the evening before your test so that your cholesterol level won't be higher than usual.
• 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 health care provider knows about any medicines, herbs, or supplements that you are taking.
• Talk to your health care provider if you have any questions.

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 health care provider when and how you will get the result of your test.

What does the test result mean?

You can use the chart below to see if your HDL cholesterol level is low.

 
HDL Cholesterol (mg/dL) 
---------------------------------------
45 or higher  good 
40 to 44      borderline low 
39 or lower   low 
---------------------------------------

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 medical history and current health. Sometimes a test needs to be repeated to check the first result. Talk to your health care provider about your result and ask questions.

If your test result is not normal, ask your health care provider:

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