ApoB

Blood test · no fasting needed

Also known as: Apolipoprotein B, Apo B

Very high-risk heart or vessel disease
Two or more major events such as a heart attack or stroke, or one event plus several high-risk features
Below 55 mg/dL
Heart or vessel disease, not very high risk
A past heart attack, stroke, stent, bypass or artery disease in the legs, without the very-high-risk features
No separate ApoB goal; below 70 mg/dL if triglycerides are raised
Diabetes with other risk factors
Diabetes plus other things that raise heart risk
Below 70 mg/dL
Diabetes, no other risk factors
Diabetes without other heart risk factors
Below 90 mg/dL
No heart disease, higher risk
Estimated 10-year heart risk of 10% or more, or age 40 to 75 with at least one heart risk factor
Below 70 mg/dL, when triglycerides are 150 to 499 mg/dL
No heart disease, lower risk
Estimated 10-year heart risk under 10%, outside the group above
Below 90 mg/dL, when triglycerides are 150 to 499 mg/dL

Your goal depends on your overall heart risk, which your physician estimates.

Units and reference ranges differ between labs.

Cutoffs: 2026 ACC/AHA Guideline on the Management of Dyslipidemia

ApoB counts the particles in your blood that carry cholesterol into artery walls. Each of these particles carries exactly one ApoB, so the result reflects how many there are. It needs no fasting.

What it tells you

Cholesterol travels in particles. Every particle that can lodge in an artery wall carries one ApoB protein, so ApoB works as a particle count.
Most of these particles are LDL. The rest are VLDL, its leftovers after fat is used, and lipoprotein(a).
LDL cholesterol measures how much cholesterol the particles carry, not how many there are. Two people with the same LDL can have different particle counts.
The two disagree most when triglycerides are high, and with diabetes or insulin resistance. There, US guidelines prefer ApoB or non-HDL cholesterol over LDL.
An ApoB of 120 mg/dL or more counts as a factor that raises heart risk.

What can throw it off

Fasting does not matter. A meal barely changes it.
High triglycerides make calculated LDL cholesterol unreliable, but not ApoB, which is measured directly.
Conditions that raise LDL cholesterol generally raise ApoB too. Examples are an underactive thyroid, kidney disease, blocked bile flow and Cushing syndrome.
So can some medicines, including steroids such as prednisone, testosterone and related hormones, some antipsychotics, and cyclosporine.
Pregnancy, the menopausal transition and rapid weight loss can shift it.
Lab methods still differ somewhat, so changes are best tracked at the same lab.

Evidence

Predicting heart disease

Strong human evidenceCEBM Level 1a

Across 12 studies of over 230,000 people, ApoB predicted heart and vessel events more strongly than LDL or non-HDL cholesterol. Genetic studies in over 650,000 people found that lower risk tracked the drop in ApoB particles, whichever way it was lowered.

Finding risk that LDL misses

Strong human evidenceCEBM Level 1b

In about 390,000 adults not on cholesterol medicine, ApoB, non-HDL cholesterol and triglycerides were weighed together. Only ApoB still predicted heart attacks. Among about 40,000 patients already on statins, again only ApoB did.

Guiding treatment

Some human evidenceCEBM Level 2b

No trial has yet compared treating to an ApoB goal with treating to an LDL goal. US guidelines call ApoB reasonable for deciding whether to step up treatment once LDL and non-HDL goals are met.

Limits

It does not say which particles are raised. The standard cholesterol panel and a one-time lipoprotein(a) test fill that in.
Guidelines treat it as a second-line test. LDL and non-HDL cholesterol remain the main goals.
For most people, ApoB and LDL agree. The disagreements cluster in people with high triglycerides, diabetes or insulin resistance.
Lab methods are not yet fully matched, so a small difference between two labs may not be real.
There is no single healthy number. The right goal depends on overall heart risk.

References

Reviewed by Shubham Gupta, MD — Founder & President · November 1, 2026

This page is for education only. It is not medical advice. Decisions about any treatment belong with a physician who knows your history.