Does this test have other names?

ApoB100, Apolipoprotein B, ApoB, Apolipoprotein (B)

What is this test?

This test measures the amount of a certain type of protein on the surface of cholesterol called apolipoprotein B-100 (ApoB) in your blood. ApoB is the main protein found in the low-density lipoproteins (LDL). LDL cholesterol is known as "bad" cholesterol because high levels of it can damage your heart and arteries.

The ApoB test helps your healthcare provider figure out your risk for cardiovascular disease. This is a disease that affects your heart and blood vessels.

Why do I need this test?

You may need this test if you have a family history of heart problems. You may also need this test if you already have had heart problems, such as a heart attack. And you may need this test if you have a high level of fats, including cholesterol and triglycerides, in your blood. High levels of fats may raise your risk for heart problems.

This test is also sometimes used to see how well treatment is working to bring down high levels of fat in your blood.

What other tests might I have along with this test?

You may also need a test for total cholesterol called a lipid profile. This test measures your blood levels of LDL cholesterol, high-density lipoprotein (HDL or "good") cholesterol, and triglycerides. Comparing the percentages gives your provider a better idea of your heart health.

You may also need blood tests for other markers that help see if you are at risk for heart disease.

What do my test results mean?

Test results may vary depending on your age, gender, health history, and other things. Your test results may be different depending on the lab used. They may not mean you have a problem. Ask your healthcare provider what your test results mean for you.

Results are given in milligrams per deciliter (mg/dL). Normal levels of ApoB-100 in adults are less than 100 mg/dL. Your risk is high if you have a result greater than 110 mg/dL.

High levels of ApoB may mean that you have a higher-than-normal risk of developing cardiovascular disease. An ApoA test (linked with "good" cholesterol) may also be done with the ApoB test. The ratio of the ApoA results and the ApoB results is sometimes used as an alternative to a total cholesterol ratio to evaluate your risk of developing cardiovascular disease. 

How is this test done?

The test is done with a blood sample. A needle is used to draw blood from a vein in your arm or hand. 

Does this test pose any risks?

Having a blood test with a needle carries some risks. These include bleeding, infection, bruising, and feeling lightheaded. When the needle pricks your arm or hand, you may feel a slight sting or pain. Afterward, the site may be sore. 

What might affect my test results?

Your test may be affected by:

• Your eating habits, especially if your diet is high in fat

• Taking medicines to lower cholesterol, such as statins

• Having certain chronic diseases, such as diabetes

How do I get ready for this test?

Follow any directions you are given about not eating or drinking anything except water for a time before the test. Ask your healthcare provider if you need to stop taking any medicines before the test. Tell your provider about all medicines, herbs, vitamins, and supplements you are taking. This includes medicines that don't need a prescription and any illegal drugs you may use.