Heart and vessels
Apolipoproteïne A1
The main protein of HDL, the 'good' cholesterol; moves almost in step with the HDL value.
Everything about this testWhat it measures
Apolipoprotein A1 (ApoA1) is the protein that HDL particles are largely made of. HDL collects excess cholesterol from the tissues and the blood vessel wall and takes it to the liver, where it is reused or excreted via the bile. According to the Dutch Society for Clinical Chemistry (NVKC), the ApoA1 level rises and falls along with HDL cholesterol. The measurement therefore gives a second view of the same cholesterol removal route.
- Low HDL function: a low value fits a higher risk of cardiovascular disease
- Rare inherited disorders with a shortage of ApoA1 and a very low HDL
- The effect of lifestyle or cholesterol-lowering treatment on the 'good' cholesterol
High
A high ApoA1 usually goes together with a high HDL cholesterol and is generally favorable. It fits regular exercise, weight loss and the use of estrogens (contraception or hormone therapy); pregnancy, some epilepsy medicines and a rare inherited disorder also give higher values. A high value does not protect against a high LDL cholesterol, smoking or high blood pressure. A high ApoA1 causes no symptoms.
Low
A low ApoA1 usually goes together with a low HDL cholesterol: the removal of cholesterol from the body then works less well, which fits a higher risk of hardening of the arteries. It occurs with smoking, overweight, untreated diabetes, long-term kidney disease and with the use of beta blockers, water pills or male hormones. A rare cause is an inherited disorder with very little ApoA1 and HDL. A low value causes no symptoms.
If your result is abnormal
The GP assesses ApoA1 together with the complete lipid profile and the overall risk profile; a low ApoA1 does not lead to a different approach than a low HDL: attention to weight, exercise, smoking and blood sugar, and if needed treatment of a raised LDL or non-HDL. With very low values without explanation, referral to an internist (specialist in internal medicine) may follow.
Reliability
ApoA1 is a risk marker and not a test that proves a disease. In the Netherlands, cardiovascular risk is estimated with SCORE2 based on non-HDL cholesterol, which follows from the standard lipid profile without an extra measurement. Because ApoA1 and HDL move almost in step, the test adds little to a measured HDL for most people. You do not need to fast for the measurement.
Limitations
- There are no Dutch cut-off values for ApoA1; the limits used come from guidelines for specialist care and from laboratory references.
- During and for a few weeks after an infection, surgery or heart attack, the value is temporarily lower.
- Smoking, alcohol, weight, exercise, pregnancy and medicines such as estrogens, beta blockers, water pills and anabolic steroids affect the value.
- Laboratories use different measurement methods; preferably compare results within the same laboratory.
How common is this
There are no separate Dutch figures for a low ApoA1; it largely moves in step with a low HDL cholesterol, which is common with overweight and type 2 diabetes. In 2024, more than 1.6 million people in the Netherlands were known to their GP with a lipid metabolism disorder. Inherited disorders with a shortage of ApoA1 are rare.
Who is this useful for
Useful as an addition in extended testing of lipid metabolism, for example with cardiovascular disease at a young age in the family or with a very low HDL cholesterol whose cause is unclear. For most people, ApoA1 adds little to the standard lipid profile, in which HDL is already measured. Without total cholesterol, HDL, LDL and triglycerides alongside it, a single ApoA1 value is hard to place.
Downsides and risks
- A low ApoA1 is sometimes read as a separate 'heart risk', while it gives the same information as HDL cholesterol, and an isolated low HDL is not treated with medicines.
Sources
Always discuss an abnormal result with your GP. If a result is strongly abnormal, we try to reach you as soon as possible. Read your result yourself as well and contact your GP if in doubt. A test does not make a diagnosis. Read more about risks and results