ApoB: the cholesterol number you may never have been tested for

What it is

Apolipoprotein B (ApoB) is a protein carried by every particle that can deposit cholesterol in the walls of your arteries: LDL, VLDL, IDL and Lp(a). Each of those particles carries exactly one ApoB molecule, so measuring ApoB is the same as counting them.

Why it matters

A standard cholesterol test reports LDL cholesterol: how much cholesterol those particles carry, not how many there are. Two people with the same LDL can have very different particle numbers. When the two measures disagree, cardiovascular risk follows ApoB more closely, because it is the number of particles entering the artery wall that drives plaque build-up.

The disagreement is most common in people with high triglycerides, type 2 diabetes, insulin resistance or excess weight around the middle. In these groups LDL can look reassuring while ApoB is high.

Targets in use

UK labs usually report ApoB in grams per litre (g/L). Some labs and most US sources use milligrams per decilitre (mg/dL): 1.0 g/L is the same as 100 mg/dL.

European guidelines set ApoB targets by overall cardiovascular risk rather than one normal range:

Your GP or lipid clinic decides which risk group applies to you, usually with a risk score such as QRISK3 and your medical history.

In HumanGens: if you have uploaded an ApoB result, you will find it in Measurements with its trend. If not, it appears as a suggested test in the cardiovascular area.

What moves it

• Diet: less saturated fat (fatty meat, butter, coconut oil) and more soluble fibre (oats, beans, lentils) lowers ApoB for most people.
• Weight: losing excess weight, especially around the waist, lowers ApoB and triglycerides.
• Activity: regular exercise has a smaller direct effect on ApoB but improves the rest of the lipid picture.
• Medication: statins and other lipid-lowering drugs lower ApoB substantially. Whether you need them is a decision for you and your doctor, based on your overall risk.

How to get it tested

ApoB is not part of the standard NHS lipid profile, but your GP or a lipid clinic can request it, and many private labs include it in their heart-health panels. You do not usually need to fast.

Sources

• Mach F, Baigent C, Catapano AL, et al. 2019 ESC/EAS Guidelines for the management of dyslipidaemias. European Heart Journal. 2020;41(1):111–188.
• Sniderman AD, Thanassoulis G, Glavinovic T, et al. Apolipoprotein B particles and cardiovascular disease: a narrative review. JAMA Cardiology. 2019;4(12):1287–1295.
• National Institute for Health and Care Excellence. Cardiovascular disease: risk assessment and reduction, including lipid modification (NG238). 2023.