Apolipoprotein AApolipoproteína A

Apolipoprotein A

Does this test have other names?

Apo A-1, apolipoprotein a-1 

What is this test?

This test measures the amount of apolipoprotein A in your blood. It helps your healthcare provider figure out your risk for cardiovascular disease.

Apolipoprotein A is a protein carried in HDL ("good") cholesterol. It helps start the process for HDL to remove bad types of cholesterol from your body. In this way, apolipoprotein A can help to lower your risk for cardiovascular disease. Although apolipoprotein A levels can be measured, it's more common to measure the HDL and LDL ("bad") cholesterol when looking at cardiovascular risk.     

Why do I need this test?

You may have this test to see if you are at increased risk for heart disease. You may also need if this test if you have already had heart problems such as a heart attack. This test is not used as often as a lipid profile. A lipid profile measures HDL and LDL cholesterol. But some studies suggest that apolipoprotein A test results are a good measure of your heart disease risk.  

This test may also help your healthcare provider fine-tune your risk if you have a family history of heart disease. 

What other tests might I have along with this test?

Your healthcare provider may also order tests that measure:

  • Lipid profile

  • LDL cholesterol

  • HDL cholesterol

  • Triglycerides

  • Total cholesterol

  • Apolipoprotein B

The accuracy of your heart disease risk is better when both apolipoprotein A and apolipoprotein B levels are measured and looked at together.

What do my test results mean?

Many things may affect your lab test results. These include the method each lab uses to do the test. Even if your test results are different from the normal value, you may not have a problem. To learn what the results mean for you, talk with your healthcare provider.

Results are given in milligrams per deciliter (mg/dL). A normal level is greater than 120 mg/dL.

Your apolipoprotein A levels may be high if you:

  • Have high levels of apolipoprotein (familial hyperalphalipoproteinemia)

  • Have a genetic disorder called familial cholesteryl ester transfer protein deficiency, or CETP

  • Take medicines containing extra estrogens

  • Take niacin

  • Take statins, a type of cholesterol-lowering medicine

  • Lose weight

Your apolipoprotein A levels may be low if you have:

  • Low levels of apolipoprotein (familial hypoalphalipoproteinemia)

  • Tangier disease, a rare inherited disorder that lowers the amount of HDL

  • Hepatocellular disorders, which are certain types of liver problems

  • Nephritic syndrome, a group of kidney problems

  • Chronic kidney (renal) failure

  • Coronary artery disease. This means the arteries carrying blood to the heart become narrowed and hardened.

  • Cholestasis, which means problems with the flow of bile from the liver

Smoking cigarettes, taking diuretics, or taking medications that contain androgens can also cause lower levels of apolipoprotein A. 

How is this test done?

The test requires a blood sample, which is drawn through a needle from a vein in your arm.

Does this test pose any risks?

Taking a blood sample with a needle carries risks that include bleeding, infection, bruising, or feeling dizzy. When the needle pricks your arm, you may feel a slight stinging sensation or pain. Afterward, the site may be slightly sore. 

What might affect my test results?

Cigarette smoking can affect this test. Certain medicines can also affect your test results. They include:

  • Niacin

  • Statins

  • Diuretics

  • Medicines containing estrogens

  • Medicines containing androgens

How do I get ready for this test?

Tell your healthcare provider if you smoke or take any medicines regularly, such as statins, diuretics, or hormone medicine. You may need to stop taking some of these medicines for the test.  In addition to these medicines, be sure your healthcare provider knows about all other medicines, herbs, vitamins, and supplements you are taking. This includes medicines that don't need a prescription and any illicit drugs you may use.