Apolipoprotein A1 (ApoA1) test
University of Rochester Medical Center; labs in Lithuania usually report ApoA1 in g/l, so compare your result with the range on your own lab report
- Updated
- 2026-09-10
- Every number with its source
What apolipoprotein A1 is
Apolipoprotein A1 (ApoA1) is the main protein making up the HDL particle, often called the "good" cholesterol. According to MedlinePlus genetics information, ApoA1 helps carry cholesterol and phospholipids from cells to the surface of the HDL particle and activates an enzyme that esterifies cholesterol. This process is called reverse cholesterol transport, in which excess cholesterol from the tissues is returned to the liver for removal. Because ApoA1 makes up most of the HDL particle, its amount in the blood is closely related to the amount of HDL cholesterol and is interpreted in a similar way: a higher ApoA1 is usually associated with a lower risk of cardiovascular disease. ApoA1 is sometimes tested together with apolipoprotein B — the protein found in LDL and other atherogenic particles — to calculate the ApoB/ApoA1 ratio as an additional marker of lipid metabolism. A rare inherited change in the APOA1 gene can cause familial HDL deficiency with a very low ApoA1, or a rarer disease in which protein builds up in the organs (amyloidosis).
Reference ranges
| Group | Range, mg/dL | Source | |
|---|---|---|---|
| Men University of Rochester Medical Center; labs in Lithuania usually report ApoA1 in g/l, so compare your result with the range on your own lab report | 110–180 | URMC accessed 2026-09-06 | |
| Women University of Rochester Medical Center; the source gives the two ranges separately and does not explain why the upper limit is higher for women | 110–205 | URMC accessed 2026-09-06 | |
According to the University of Rochester Medical Center source, women are given an apolipoprotein A1 range of 110–205 mg/dL, while for men it is narrower, 110–180 mg/dL — the same lower limit, but a higher upper one. The source presents these two ranges separately, but it does not explain why the upper limit is higher for women: a reason (for example a hormonal effect) is not mentioned in the text.
Important: these figures are given in mg/dL, whereas laboratories in Lithuania most often measure ApoA1 in g/l, so you should compare your own result with the range stated on your laboratory report rather than directly with these mg/dL figures. It is also worth noting that different laboratories may use slightly different methods and reference ranges, so a result is always worth interpreting together with the range the laboratory provides.
When ApoA1 is tested
- To assess the risk of cardiovascular disease together with other lipid markers — total cholesterol, LDL and HDL
- When HDL cholesterol is low and the risk is to be assessed more fully
- Together with apolipoprotein B, to calculate the ApoB/ApoA1 ratio
- When there has been early heart disease in the family before the age of 50
- When a rare inherited familial HDL deficiency is suspected
How to prepare
- No special preparation is usually needed, but as with other lipid markers the laboratory may ask you not to eat for a short while before the sample is taken — check the exact instructions with your laboratory
- Tell your doctor about any medicines and supplements you take, as some of them can affect the result
A raised ApoA1
A higher than usual amount of apolipoprotein A1 (ApoA1) is most often not a cause for concern, because a higher amount of HDL, the "good" cholesterol, is usually associated with a lower risk of cardiovascular disease. Rarer causes are genetic conditions or certain medicines.
- Familial hyperalphalipoproteinaemia, or inherited cholesteryl ester transfer protein (CETP) deficiency
- Taking medicines that contain oestrogen, niacin or statins
- Recent weight loss
What to discuss with a doctor:
- HDL cholesterol and the whole lipid panel — interpreted together with ApoA1
- The medicines and supplements being taken that could affect the result
A low ApoA1
A low amount of apolipoprotein A1 (ApoA1) reflects a small amount of HDL, the "good" cholesterol, because ApoA1 is the main protein of this particle. According to MedlinePlus, rare inherited mutations in the APOA1 gene cause familial HDL deficiency — a very low HDL/ApoA1 and an increased likelihood of cardiovascular disease, often appearing before the age of 50.
- Inherited mutations in the APOA1 gene that cause familial HDL deficiency
- A generally low amount of HDL cholesterol, since ApoA1 makes up most of this particle
What to discuss with a doctor:
- HDL cholesterol and the whole lipid panel — interpreted together with ApoA1
- Family history: whether there has been heart disease in the family before the age of 50
- Apolipoprotein B and the ApoB/ApoA1 ratio, for an overall assessment of lipid metabolism
- When to repeat the test if the result is low
Full site in Lithuanian: proactiva.app
Frequently asked questions
›What is the normal apolipoprotein A1 (ApoA1) range?
The MedlinePlus sources reviewed do not give a specific numeric reference range with units — they state only that a higher ApoA1/HDL is usually associated with a lower risk of cardiovascular disease. Your laboratory's exact range in g/l will be on your result report, together with your doctor's comment.
›What is apolipoprotein A1?
ApoA1 is the main protein making up the HDL particle, known as the "good" cholesterol. According to MedlinePlus, it helps carry excess cholesterol from the tissues back to the liver for removal — a process called reverse cholesterol transport.
›How does ApoA1 differ from an HDL cholesterol test?
An HDL cholesterol test measures the amount of cholesterol in HDL particles, while an ApoA1 test measures the protein that makes up those particles. Because ApoA1 is the main component of HDL, both markers usually move in the same direction and are often interpreted together.
›What does a low ApoA1 mean?
A low ApoA1 reflects a small amount of HDL. According to MedlinePlus, rare inherited mutations in the APOA1 gene cause familial HDL deficiency, which is associated with an increased likelihood of cardiovascular disease, often appearing before the age of 50. The result should be discussed with a doctor together with the whole lipid panel.
›What is the ApoB/ApoA1 ratio?
It is the ratio of apolipoprotein B to apolipoprotein A1, which is sometimes calculated as an additional marker of lipid metabolism alongside the usual lipid panel. This ratio is discussed in more detail on a [separate Proactiva page](/en/apob-apoa1-ratio-explained).
›How do I prepare for an ApoA1 blood test?
No special preparation is usually needed, but as with other lipid markers the laboratory may ask you not to eat for a short while before the sample is taken. Tell your doctor about any medicines and supplements you take, as they can affect the result.
Sources
Related markers
This site is not an emergency service. If severe chest or head pain, breathlessness, confusion, difficulty speaking, heavy bleeding or another acute problem has come on suddenly — do not wait for tests, call 112.
This information is not a diagnosis and does not replace a consultation with a doctor. Reference ranges depend on the laboratory, your age and sex — always compare your result with the range printed on your own report.