Apolipoprotein B
The main protein on every LDL, VLDL and Lp(a) particle, giving a direct count of atherogenic particles.
| Typical reference range | below 89 mg/dL |
| Commonly cited optimal range | below 80 mg/dL |
Ranges vary by laboratory, method, age and sex: always use the range printed on your own report. Why labs differ.
What it measures
ApoB-100 is the structural protein that wraps each LDL, IDL, VLDL and Lp(a) particle, with exactly one ApoB per particle. Measuring ApoB therefore estimates the total number of potentially plaque-forming lipoproteins.
Why it matters
ApoB is considered by many lipid experts to be the most accurate single lipid marker of atherosclerotic risk, especially when LDL-C is discordant (e.g. with high triglycerides, diabetes or obesity). European and Canadian guidelines endorse it as a treatment target.
What a high result can mean
High ApoB results from the same causes as high LDL-C and non-HDL-C: genetics, saturated fat intake, insulin resistance, obesity, hypothyroidism, kidney disease and some medications. ApoB can be high even when LDL-C appears normal.
What a low result can mean
Low ApoB is associated with lower cardiovascular risk. Very low values without treatment are rare and may reflect genetic hypobetalipoproteinemia, malnutrition or liver disease.
What affects the result
Fasting is not required and the assay is well standardized. ApoB falls with statins, ezetimibe, PCSK9 inhibitors, dietary fat quality changes, soluble fiber and weight loss. Commonly cited targets are below 80 mg/dL for primary prevention and below 60-65 mg/dL for high-risk individuals.
Units and conversion
Usually reported in mg/dL.
- From g/L: multiply by 100 to get mg/dL
- From mg/L: multiply by 0.1 to get mg/dL
Also called on lab reports
ApoB, Apo B, Apolipoprotein B-100, Apo B-100, Apo-B, Apolipoprotein B, Serum
Related tests: Lipids & Cardiovascular Risk
This page is educational and does not replace advice from a healthcare professional.