- LDL measures cholesterol in LDL particles, non-HDL adds all other harmful particles, and apoB counts them.
- Non-HDL is free: it is simply total cholesterol minus HDL, from the same test.
- When triglycerides are high, non-HDL and apoB are more reliable than LDL.
- Everyone should have Lp(a) measured once; about 1 in 5 people have a level that raises risk.
Open a cholesterol report and you may see several numbers that all seem to describe “bad” cholesterol: LDL, non-HDL, and sometimes apoB. Your doctor might focus on one, a lab might flag another, and articles online argue for a third. So which one should you watch?
The short answer: they measure the same underlying problem, too many plaque-causing particles, from different angles. Most of the time they agree. When they do not, knowing the difference can change your picture of risk. If you are new to these terms, start with understanding cholesterol numbers.
Three views of the same problem
The cholesterol carried inside LDL particles. Often calculated from other results rather than measured directly.
Total cholesterol minus HDL. Captures cholesterol in LDL, VLDL, remnants and Lp(a).
Counts the particles themselves, since each harmful particle carries one apoB. See apoB explained.
How they compare
| LDL cholesterol | Non-HDL cholesterol | ApoB | |
|---|---|---|---|
| What it measures | Cholesterol in LDL only | Cholesterol in all apoB particles | Number of apoB particles |
| Extra cost | None, standard panel | None, worked out from the panel | A separate test |
| Fasting needed? | Usually not | No | No |
| Accuracy with high triglycerides | Weaker; calculated LDL can be wrong | Good | Best |
| Main use in guidelines | Primary treatment target | Secondary target, especially with high triglycerides or diabetes | Secondary target and risk check |
Based on the 2019 ESC/EAS dyslipidaemia guidelines and the 2018 AHA/ACC cholesterol guideline.
Working out your non-HDL
You can calculate non-HDL cholesterol yourself from any standard report. Take your total cholesterol and subtract your HDL. For example, a total of 210 mg/dL with an HDL of 40 gives a non-HDL of 170 mg/dL. Targets are set about 30 mg/dL (0.8 mmol/L) above the matching LDL target.
Targets for each marker by risk level (ESC/EAS 2019, mg/dL)
Mach et al., Eur Heart J 2020. Values are upper limits (“under”). In mmol/L, non-HDL targets are 3.4, 2.6 and 2.2.
When the numbers disagree
In most healthy people, LDL, non-HDL and apoB tell the same story. They split apart most often in people with insulin resistance, type 2 diabetes, fatty liver, obesity or high triglycerides. In these conditions the liver releases more triglyceride-rich particles, and LDL particles become smaller and carry less cholesterol each.
Why LDL can underestimate risk in insulin resistance
There is also a measurement problem. Most labs calculate LDL from total cholesterol, HDL and triglycerides. The classic formula becomes less accurate when triglycerides are high or LDL is very low, and is not used at all above 400 mg/dL of triglycerides. Non-HDL and apoB avoid this problem.
In a meta-analysis of 12 studies with about 234,000 people, apoB was the strongest predictor of heart risk, non-HDL came second and LDL third. The practical ranking many experts use: apoB if you have it, non-HDL if you do not, and LDL alongside both.
Why LDL is still the main target
If apoB predicts risk better, why do guidelines still lead with LDL? Mainly history and evidence. Almost every major cholesterol trial, from statins to ezetimibe to PCSK9 inhibitors, set its goals and reported its results in terms of LDL. LDL is also measured in every lab worldwide at low cost. For most people, lowering LDL lowers non-HDL and apoB at the same time, so the three move together. The extra markers matter most as a safety net: they catch people whose LDL looks reassuring but whose particle count is not.
See the bigger picture. Cholesterol is one of several linked numbers. Try our Metabolic Health Score to see how your waist, blood pressure, blood sugar and lipids fit together.
Lp(a): the once-in-a-lifetime test
Lipoprotein(a), or Lp(a), is an LDL-like particle with an extra protein attached. It promotes both plaque and blood clots. Your level is mostly set by your genes, stays fairly stable through life and barely responds to diet or exercise. Standard lipid panels do not include it.
Kronenberg et al., EAS consensus, Eur Heart J 2022; Mach et al., ESC/EAS guidelines 2019.
The European guidelines advise measuring Lp(a) at least once in every adult’s lifetime. It is especially worth checking if you or a close relative had a heart attack or stroke at a young age, or if your LDL stays high despite treatment. Results come in mg/dL or nmol/L, which cannot be converted exactly, so check which unit your lab uses. Under 30 mg/dL (75 nmol/L) is considered low risk.
A high Lp(a) does not mean a heart attack is inevitable. It means your other risk factors deserve extra attention: a lower LDL target, good blood pressure, no smoking. Medicines that specifically lower Lp(a) are being studied; ask your doctor about current options.
Tell your family. Lp(a) and very high LDL often run in families. If yours is high, parents, siblings and children may benefit from testing too. Talk to your doctor about what your results mean for you.
MythYou need expensive advanced tests to know your risk.
FactNon-HDL cholesterol comes free with every standard panel. Add apoB when triglycerides are high and Lp(a) once in life, and you have a very complete picture.
Common questions
Which number should I track over time?
Track the one your doctor uses as your target, usually LDL. If you have diabetes or high triglycerides, also watch non-HDL or apoB.
My LDL is at target but non-HDL is not. What now?
That usually means triglyceride-rich particles are high. Cutting sugar, refined carbs and alcohol, and losing weight if needed, often helps. Discuss further steps with your doctor.
Is the LDL on my report calculated or measured?
Most reports show a calculated LDL, sometimes marked “calc”. If your triglycerides are high, ask whether a directly measured LDL, non-HDL or apoB would give a truer picture.
Can diet lower Lp(a)?
Not meaningfully. Focus on what you can change: LDL, blood pressure, blood sugar, activity and not smoking.
- LDL, non-HDL and apoB all reflect plaque-causing particles, from different angles.
- Non-HDL is total minus HDL and needs no extra test.
- With insulin resistance or high triglycerides, non-HDL and apoB are more reliable than LDL.
- Check Lp(a) once in adulthood; about 1 in 5 people have a raised level.
- Next: What Causes High LDL Cholesterol?.
Sources
- Mach F, Baigent C, Catapano AL, et al. 2019 ESC/EAS Guidelines for the management of dyslipidaemias: lipid modification to reduce cardiovascular risk. Eur Heart J. 2020;41(1):111–188.
- Kronenberg F, Mora S, Stroes ESG, et al. Lipoprotein(a) in atherosclerotic cardiovascular disease and aortic stenosis: a European Atherosclerosis Society consensus statement. Eur Heart J. 2022;43(39):3925–3946.
- Grundy SM, Stone NJ, Bailey AL, et al. 2018 AHA/ACC/AACVPR/AAPA/ABC/ACPM/ADA/AGS/APhA/ASPC/NLA/PCNA Guideline on the Management of Blood Cholesterol. Circulation. 2019;139(25):e1082–e1143.
- Sniderman AD, Williams K, Contois JH, et al. A meta-analysis of low-density lipoprotein cholesterol, non-high-density lipoprotein cholesterol, and apolipoprotein B as markers of cardiovascular risk. Circ Cardiovasc Qual Outcomes. 2011;4(3):337–345.
- Sniderman AD, Thanassoulis G, Glavinovic T, et al. Apolipoprotein B particles and cardiovascular disease: a narrative review. JAMA Cardiol. 2019;4(12):1287–1295.
- Nordestgaard BG, Langsted A, Mora S, et al. Fasting is not routinely required for determination of a lipid profile: clinical and laboratory implications including flagging at desirable concentration cut-points. A joint consensus statement from the European Atherosclerosis Society and European Federation of Clinical Chemistry and Laboratory Medicine. Eur Heart J. 2016;37(25):1944–1958.
This article is for general education and is not a substitute for advice from your own doctor or healthcare team.