To determine whether or not you have an adequate level of apo A-I, especially if you have a low level of high-density lipoprotein (HDL-C), and to help determine your risk of developing cardiovascular disease (CVD)
Apo A-I
Apo A-I
Also Known As
Apo A
Formal Name
Apolipoprotein A-I
This article was last reviewed
on
This article waslast modified
on September 28, 2018.
At a Glance
Why Get Tested?
When To Get Tested?
When you have a low value of HDL-C, high cholesterol and triglycerides (hyperlipidemia), and/or a family history of CVD; when your healthcare provider is trying to assess your risk of developing heart disease; when monitoring the effectiveness of lipid treatment and/or lifestyle changes
Sample Required?
A blood sample drawn from a vein in your arm; blood from the prick of a baby's heel or finger
Test Preparation Needed?
No test preparation is needed; however, since this test may be performed at the same time as a complete lipid profile, fasting for at least 12 hours may be required.
Accordion Title
Common Questions
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How is it used?
Apolipoprotein A-I (apo A-I) may be ordered, along with other lipid tests, as part of a profile to help determine a person's risk of developing cardiovascular disease (CVD). It may be used as an alternative to a high-density lipoprotein (HDL) test, but it is not generally considered "better" or more informative than HDL and is not ordered routinely.
Apo A-I is a protein that has a specific role in the metabolism of lipids and is the main protein component in HDL, the "good cholesterol". HDL removes excess cholesterol from cells and takes it to the liver for recycling or disposal. Levels of apo A-I tend to rise and fall with HDL levels, and deficiencies in apo A-I correlate with an increased risk of developing CVD.
An apo A-I test may sometimes be ordered to:
- Help diagnose inherited or acquired conditions that cause apo A-I deficiencies
- Help evaluate people who have a personal or family history of heart disease and/or high cholesterol and triglycerides or low HDL
- Monitor the effectiveness of lifestyle changes and lipid treatments
An apo A-I may be ordered along with an apolipoprotein B (apo B) test to determine an apo B/apo A-I ratio. This ratio is sometimes used as an alternative to a total cholesterol/HDL ratio (sometimes reported as part of a lipid profile) to evaluate risk for developing CVD.
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When is it ordered?
Apo A-I may be measured when someone has a personal or family history of abnormal lipid levels and/or premature CVD. It may be ordered when a healthcare practitioner is trying to determine the cause of a person's high cholesterol and/or suspects it may be due to a disorder that is causing a deficiency in apo A-I.
Apo A-I may be ordered along with apo B when a healthcare practitioner wants to check an apo B/apo A-I ratio as a CVD risk indicator, to evaluate the "bad" to "good" cholesterol.
Apo A-I may be ordered, along with other tests, when someone has undergone lipid-lowering treatment or lifestyle changes, such as decreased dietary fat and increased regular exercise, to monitor the effectiveness of the changes.
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What does the test result mean?
Low levels of apo A-I are usually associated with low levels of HDL and impaired clearance of excess cholesterol from the body. Low levels of apo A-I, along with high concentrations of apo B, are associated with an increased risk of cardiovascular disease. High levels of apo A-I is considered protective and can be independent of HDL levels.
There are some genetic disorders that lead to deficiencies in apo A-I (and therefore to low levels of HDL). People with these disorders tend to have abnormal lipid levels, including high levels of low-density lipoprotein (LDL – the "bad" cholesterol). Frequently, they have accelerated rates of atherosclerosis. These genetic disorders are primary causes of low apo A-I.
Changes in levels of apo A-I may also be associated with other factors. Some of the conditions that contribute to decreases or increases in apo A-I are listed below.
Apo A-I may decrease with:
- Chronic kidney disease
- Use of drugs such as: androgens, beta blockers, diuretics, and progestins (synthetic progesterone)
- Smoking
- Uncontrolled diabetes
- Obesity
Apo A-I may increase with:
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Is there anything else I should know?
The concentration of apo A-I reflects the amount of HDL in the serum. Since women tend to have higher HDL, they also have higher levels of apo A-I.
The apo A-I test is not routinely ordered. Healthcare practitioners still have to determine the best uses for the apo A-I and other tests for emerging cardiac risk markers (such as apo B, hs-CRP, and Lp(a)). They offer additional information in specific situations but are not meant to replace the lipid tests already routinely available.
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What can I do to raise my apo A-I?
Behaviors that tend to raise HDL also raise apo A-I. Regular exercise is one of the best ways to raise HDL and apo A-I. By decreasing the saturated fat in your diet, maintaining a healthy weight, and exercising, you can help decrease your risk of developing heart disease.
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Can an apo A-I test be performed in my doctor's office or at home?
No, the apo A-I test requires specialized equipment and is not offered by every laboratory. Your blood may need to be sent to a reference laboratory for testing.