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Low-density Lipoprotein Cholesterol

What Is LDL Cholesterol?

Cholesterol is a fat-like substance. It keeps cells and tissues healthy. LDL cholesterol is often called "bad" cholesterol. LDL can lead to a buildup of plaque in the arteries. Higher levels of LDL are linked to a higher risk of heart disease and stroke.

Reason for the Test

The test is done to check for heart disease risk. LDL is a part of a lipid profile that checks different types of cholesterol levels in the blood. LDL levels may be a better predictor of heart disease risk than total cholesterol or high-density lipoprotein (HDL) levels.

Adults aged 20 years and older should get checked every 4 to 6 years. People with cholesterol problems or who have a high risk of heart disease may need to do this more often.

Type of Sample Taken

A blood sample will be taken from a vein in the arm.

Prior to Collecting the Sample

You may not need to do anything before the test. However, your doctor may ask you to not eat or drink anything other than water for 9 to 12 hours before the test.

Talk to your doctor about medicines or supplements you take. They may affect the results.

During the Sample Collection

You will be asked to sit. An area inside your elbow will be cleaned. A large band will be tied around your arm. The needle will then be inserted into a vein. A tube will collect the blood from the needle. The band on your arm will be removed. Once all the blood is collected, the needle will be removed. Some gauze will be placed over the site to help stop bleeding. You may also be given a bandage to place over the site. The process takes about 5 to 10 minutes.

Cholesterol tests can also be done with a home kit, or at worksites, health fairs, or drug stores. Get retested by your doctor if results show you may have high total cholesterol.

After Collecting the Sample

After the blood sample is taken, you may need to stay seated for 10 to 15 minutes. If you are lightheaded, you may need to stay seated longer. When you feel better, you can leave.

A bit of blood may ooze from the vein beneath the skin. It will cause a bruise. A bruise will usually fade in a day or two.

Call your doctor right away if you have redness, swelling, lasting bleeding, or pain.


Results can take 1 to 2 days.

The risk of heart disease and stroke gets higher as LDL levels rise. Treatment may be needed if the number is high enough. Your doctor will help you find ways to lower LDL levels to a healthy range.

Cholesterol levels can change because of other health conditions such as diabetes, pregnancy, or a flare-up of arthritis. You may need further testing

Talk to your doctor about your test results. A test can point to an illness that you do not have. It can also miss an illness that you may have. The doctor will check your symptoms and all test results before making a diagnosis.


Hypercholesterolemia. EBSCO DynaMed website. Available at:https://www.dynamed.com/topics/dmp~AN~T114250/Hypercholesterolemia. Updated April 16, 2019. Accessed May 22, 2019.

LDL cholesterol. Lab Tests Online—American Association for Clinical Chemistry website. Available at: https://labtestsonline.org/tests/ldl-cholesterol. Updated May 9, 2019. Accessed May 22, 2019.

What your cholesterol levels mean. American Heart Association website. Available at: https://www.heart.org/en/health-topics/cholesterol/about-cholesterol/what-your-cholesterol-levels-mean. Accessed May 22, 2019.

Last reviewed March 2019 by EBSCO Medical Review Board Marcin Chwistek, MD  Last Updated: 5/22/2019