Single marker guide · Apolipoprotein B (ApoB)
Heart disease is not caused by cholesterol. It is caused by the particles that carry cholesterol into your artery walls, and ApoB counts them. It predicts heart attack and stroke risk better than LDL, it exposes the one in five people whose "normal" cholesterol is hiding a high particle count, and the NHS does not test it. If you only ever learn one cardiovascular number, this is the one.
Venous draw at 103 UK clinics or at home. UKAS-accredited laboratory. Report reviewed by a medical professional.
The short answer
Cholesterol does not float freely in blood. It travels inside lipoprotein particles, and each of the particles that can enter an artery wall and start a plaque, LDL, VLDL, IDL and Lp(a), carries exactly one molecule of apolipoprotein B. So an ApoB test is a particle count. LDL cholesterol, the number your GP quotes, measures the total cholesterol cargo those particles are carrying. The two usually move together, but not always, and when they disagree it is the particle count that predicts what happens to you.
The disagreement matters most in exactly the people at highest risk. Insulin resistance, high triglycerides, central weight gain and a fatty liver all produce lots of small, cholesterol-poor particles. Each one carries less cargo, so LDL cholesterol looks fine, but there are far more of them, so ApoB is high, and it is the number of particles hitting the artery wall that drives plaque. That is the one in five: normal cholesterol, high ApoB, and no idea, because nobody tested it. Cholesterol blood test guide.
Reference ranges
| ApoB result | Category | What it means |
|---|---|---|
| Below 0.65 g/L | Very low risk | The level European guidelines set as the goal for people already at very high cardiovascular risk. For a healthy adult, this is where lifetime risk of a cardiac event is lowest. |
| 0.65 to 0.80 g/L | Low risk | Below the target most preventive cardiologists use for healthy adults. Comfortable, particularly if Lp(a) is also low. |
| 0.80 to 1.00 g/L | Moderate | Above optimal, though inside many laboratories' reference range. Worth acting on with diet and exercise, and worth reading alongside Lp(a), triglycerides and insulin. |
| 1.00 to 1.30 g/L | High | A meaningful particle burden. Discuss with your GP, especially with any family history, raised Lp(a), high blood pressure or insulin resistance. Lifestyle change usually moves it; medication may be appropriate. |
| Above 1.30 g/L | Very high | Above the upper reference limit. Genetic causes such as familial hypercholesterolaemia are possible. A GP conversation about treatment is warranted, not optional. |
UK laboratories report ApoB in g/L; some quote mg/dL (multiply g/L by 100). Reference ranges typically run 0.5 to 1.3 g/L, which describes the population rather than the risk. TrueVitals reports show your result against both the laboratory range and the risk-based targets, with the reasoning written out.
Why it matters
Every other page in this series has a symptoms section. This one does not, because atherosclerosis has no symptoms until the day it does, and for a quarter of people the first symptom is a fatal heart attack. Plaque builds silently over decades in proportion to the number of ApoB particles that pass through the artery wall and the number of years they do it. A high ApoB at 35 is not an emergency. It is a forecast, and it is the most changeable forecast in medicine.
Large studies including UK Biobank and the INTERHEART study found ApoB, or the ApoB to ApoA1 ratio, a stronger predictor of heart attack than LDL cholesterol. European Society of Cardiology guidelines now list ApoB as the preferred measure where available.
Around half of people admitted with a first heart attack have LDL cholesterol in the normal range. Discordance between LDL and ApoB explains a good share of them, and it is invisible unless ApoB is measured.
Statins lower LDL cholesterol reliably but can leave particle numbers higher than the LDL figure suggests, especially in people with insulin resistance. ApoB is the number that tells you whether residual risk remains. Heart health blood test guide.
Who should test
Because ApoB is stable, cheap to measure and changeable, one baseline in your thirties is the sensible default for anyone. The case is stronger if any of the following apply: a parent or sibling with heart disease before 60; a South Asian background, where cardiovascular risk runs higher at the same cholesterol level; high triglycerides, a large waist, prediabetes or a fatty liver, all of which produce the small-particle pattern that hides from LDL; blood pressure above 130/80; being a woman after the menopause, when ApoB typically rises sharply; already taking a statin and wanting to know if it is doing enough; or a raised Lp(a), which compounds every ApoB particle's effect. Health check at 40 for men.For women.
Read it in context
ApoB on its own tells you your particle count. Read alongside the right markers, it tells you why it is high, how urgent it is, and which lever will move it.
Lipoprotein(a) is an ApoB particle with an extra genetic component that makes it stickier and more inflammatory. It is set at birth and untouched by diet. A high Lp(a) means every ApoB particle carries more risk, and the ApoB target should be lower to compensate. Both are in Ultimate. Lp(a) blood test guide.
High triglycerides with low HDL is the fingerprint of small, dense particles and insulin resistance. When it sits beside a high ApoB and a normal LDL, the cause is metabolic and the fix is carbohydrate, weight and movement rather than saturated fat alone.
Insulin resistance is the engine behind most discordant ApoB. Measuring it tells you whether the particle count will respond to metabolic change, and how much cardiovascular risk is coming from blood sugar as well. Insulin and HOMA-IR are in Ultimate. Prediabetes guide.
Particles cause plaque; inflammation decides whether plaque ruptures. A high ApoB with a raised hs-CRP is a different risk profile from a high ApoB with a low one, and it changes how hard to push.
A fatty liver overproduces VLDL, the particles that become small dense LDL. Raised ALT or GGT next to a high ApoB points to the liver as the source, and to the diet changes that reverse fatty liver as the most effective treatment. Liver blood test guide.
ApoA1 is the protein on protective HDL particles. The ApoB to ApoA1 ratio was the single strongest lipid predictor of heart attack in the INTERHEART study across 52 countries. The Signature panel reports both and the ratio.
Which test
Advanced
74 biomarkers · £269
ApoB with the full lipid profile, triglycerides, HDL, hs-CRP, HbA1c, liver enzymes, full thyroid, iron and hormones. The right choice for a first cardiovascular baseline.
View AdvancedMost chosen
Ultimate
114 biomarkers · £349
Everything in Advanced plus Lp(a), fasting insulin, HOMA-IR and C-peptide, the markers that explain a high ApoB and decide how urgent it is. The cardiovascular panel a cardiologist would order.
View UltimateSignature
230 biomarkers · £799
Processed by Randox. Adds ApoA1 and the ApoB:ApoA1 ratio, homocysteine and extended cardiovascular markers, plus physical measurements. The deepest cardiovascular picture available privately in the UK.
View SignatureClinic draw £19 at 103 UK clinics. At-home phlebotomist £39 across 200+ areas. Fast from 10pm the night before. Pay monthly available.
Honest comparison
If you are already on lipid-lowering treatment with a cardiologist and simply want to track ApoB between reviews, a standalone ApoB test from Medichecks costs around £49 and is perfectly adequate. Some GPs will also add ApoB to an NHS lipid profile on request; it costs the NHS very little and it is worth asking.
A panel is the better choice for a first look, because a high ApoB on its own leaves the important questions open: is it genetic or metabolic, is Lp(a) compounding it, is inflammation present, is the liver driving it. Those answers decide whether the right response is diet, medication or both, and they come from markers a single test does not include. See how every UK provider compares.
After the result
Your particle count is low. Check Lp(a) once, keep the habits that got you here, and retest in a year or two. If Lp(a) is high, aim to keep ApoB toward the bottom of the range.
The levers that reliably lower ApoB: replacing saturated fat with unsaturated, 30 grams of fibre a day, losing visceral weight if you carry it, and regular exercise. Expect a 10 to 20% fall over three months if you do them properly. Your report tells you which apply to you.
Take your report to your GP. Depending on your overall risk, family history and Lp(a), this is the range where guidelines support considering medication alongside lifestyle. Retest at three to six months whichever route you take; your second report compares against your first automatically.
This page is general information, not medical advice. If you have chest pain, breathlessness on exertion or pain radiating to the arm or jaw, seek urgent medical care.
FAQs
Apolipoprotein B is the structural protein on every lipoprotein particle that can cause atherosclerosis: LDL, VLDL, IDL and Lp(a). Each particle carries exactly one ApoB, so measuring ApoB counts the number of plaque-forming particles in your blood. It is reported in g/L in the UK.
As a predictor of heart attack and stroke, yes, and European cardiology guidelines now prefer it where available. LDL cholesterol measures cholesterol cargo; ApoB measures particle number, and it is particle number that drives plaque. The two disagree in around one in five people, almost always those with insulin resistance or high triglycerides, and ApoB is right when they do.
Below 0.8 g/L is the target most preventive cardiologists use for healthy adults, and below 0.65 g/L is the European guideline goal for people at very high risk. Laboratory reference ranges typically run 0.5 to 1.3 g/L, but that describes the population, not the risk. TrueVitals reports show both.
It is not part of any routine NHS lipid check, which uses total, HDL and non-HDL cholesterol. Some GPs will add it on request, and lipid clinics use it, but most people will not get it without asking. A private panel includes it as standard. What to ask your GP for.
ApoB itself is barely affected by a recent meal, which is one of its advantages over triglycerides. TrueVitals panels also include glucose, insulin and triglycerides, so we ask you to fast from 10pm the night before and drink water as normal.
Replacing saturated fat with unsaturated fat, increasing soluble fibre, losing visceral fat, exercising regularly and reducing refined carbohydrate all lower ApoB, typically by 10 to 20% over a few months. Where that is not enough, or where Lp(a) or family history raises the stakes, statins and ezetimibe lower ApoB substantially and your GP can advise.
A standalone ApoB test is around £49. A TrueVitals Advanced panel is £269 and includes ApoB with a full lipid profile, hs-CRP, HbA1c, liver enzymes and 68 other markers; Ultimate at £349 adds Lp(a), fasting insulin and HOMA-IR, the markers that explain a high result.
Lp(a) is a specific type of ApoB particle with an extra protein attached that makes it more likely to cause plaque and clots. ApoB counts all plaque-forming particles including Lp(a); the Lp(a) test isolates that genetic fraction. Both matter, and a high Lp(a) means your ApoB target should be lower.
74 to 230 biomarkers. Venous draw at 103 UK clinics or at home. A report that tells you what your results mean and what to do next.
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