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 health care 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. Apolipoprotein A levels can be measured. But it's more common to measure the HDL and LDL ("bad") cholesterol when looking at cardiovascular risk.
Why do you need this test?
You may need this test to see if you are at increased risk for heart disease. You may also need 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 health care provider fine-tune your risk if you have a family history of heart disease.
What other tests might you have along with this test?
You may also need tests that measure:
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Lipid profile.
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LDL cholesterol.
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HDL cholesterol.
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Triglycerides.
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Total cholesterol.
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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 your 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 health care provider what your test results mean for you.
Results are given in milligrams per deciliter (mg/dL). For men, the normal range is 110 to 180 mg/dL; for women, the normal range is 110 to 205 mg/dL.
Your apolipoprotein A levels may be high if you:
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Have high levels of apolipoprotein (familial hyperalphalipoproteinemia).
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Have a genetic disorder called familial cholesteryl ester transfer protein deficiency.
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Take medicines containing extra estrogens.
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Take niacin.
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Take statins, a type of cholesterol-lowering medicine.
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Lose weight.
Your apolipoprotein A levels may be low if you have:
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Low levels of apolipoprotein (familial hypoalphalipoproteinemia).
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Tangier disease, a rare inherited disorder that lowers the amount of HDL.
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Hepatocellular disorders, which are certain types of liver problems.
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Poorly controlled diabetes.
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Nephritic syndrome, a group of kidney problems.
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Chronic kidney (renal) failure.
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Coronary artery disease. This means the arteries carrying blood to the heart become narrowed and hardened.
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Cholestasis, which means problems with the flow of bile from the liver.
Smoking cigarettes, taking diuretics, or taking medicines that contain androgens can also cause lower levels of apolipoprotein A.
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 your test results?
Cigarette smoking can affect this test.
Certain medicines can affect your test results. They include:
How do you get ready for this test?
Tell your health care provider if you smoke or take any medicines regularly, such as statins, diuretics, or hormone medicine. Follow your provider's directions about whether or not you need to stop taking some of these medicines for 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.