Apolipoprotein B (ApoB)

Apolipoprotein B (ApoB) is the protein found on all cholesterol particles that can cause hardening of the arteries: LDL, VLDL, IDL and lipoprotein(a). Each particle carries exactly one ApoB molecule, so the ApoB value reflects the number of these particles, while LDL cholesterol measures the amount of cholesterol inside them. ApoB and LDL usually rise and fall together. They diverge in people with many small, cholesterol-poor LDL particles, such as with overweight, high triglycerides and type 2 diabetes; LDL then underestimates the risk and ApoB (or non-HDL) gives a better picture.

• Raised risk of cardiovascular disease due to a large number of LDL and VLDL particles
• Risk underestimated by LDL cholesterol in people with high triglycerides, overweight or diabetes
• Effect of cholesterol-lowering treatment, also when LDL cannot be calculated reliably because of high triglycerides

The GP assesses ApoB alongside LDL, non-HDL and the overall risk profile; a raised ApoB does not lead to a different approach than a raised LDL or non-HDL: lifestyle, a repeat measurement and, at high risk, a statin. With strongly raised values or a family history, referral for testing for inherited high cholesterol may follow.

ApoB is a risk marker, not a test that proves a disease. In the Netherlands, risk is estimated with SCORE2 based on non-HDL cholesterol, and treatment is guided by LDL or non-HDL. According to the multidisciplinary Dutch cardiovascular risk management guideline (CVRM, Richtlijnendatabase), ApoB is a comparable measure of the harmful particles to non-HDL; non-HDL follows from the standard lipid profile without an extra measurement. ApoB mainly adds value when LDL and non-HDL diverge. You do not need to fast for this test.

• There are no Dutch cut-off values for ApoB; the limits used come from international guidelines and laboratory references.
• During and for a few weeks after an acute illness, surgery or heart attack, the value is temporarily lower.
• Pregnancy, thyroid function, kidney and liver disease and medicines (corticosteroids, some beta blockers, estrogens, cholesterol-lowering medicines) affect the value.
• Laboratories use different measurement methods; preferably compare results within the same laboratory.

There are no separate Dutch figures for a raised ApoB; it largely goes together with a raised LDL. In 2024, more than 1.6 million people in the Netherlands were known to their GP with a disorder of fat metabolism, including high cholesterol; that is about 9 in 100 inhabitants, most often between the ages of 55 and 70.

Useful as an addition to the standard lipid profile in people with high triglycerides, overweight, type 2 diabetes or the metabolic syndrome, in whom LDL can underestimate the risk, and for monitoring treatment when LDL cannot be calculated reliably. For most people, ApoB adds little to LDL and non-HDL, because the values usually rise together. Without total cholesterol, HDL and triglycerides alongside it, a single ApoB value is hard to interpret.

• ApoB is often presented online as a 'better' test than LDL; for most people it gives the same information, and an abnormal value without the complete profile can lead to unnecessary worry.

• NHG-Standaard Cardiovasculair risicomanagement (M84)
• NVKC, allesovertesten.nl: Apo B
• FMS Richtlijnendatabase, richtlijn CVRM: Non-HDL-C bij CVRM
• FMS Richtlijnendatabase, richtlijn CVRM: Nuchter bloedprikken bij CVRM
• VZinfo (RIVM): Cholesterol, op basis van Nivel Zorgregistraties Eerste Lijn 2024