ApoB to ApoA1 ratio calculator
Compares ApoB (the protein on particles that can build up in arteries) with ApoA1 (the main HDL protein). A higher ratio is linked to more heart attacks. Type your results in the units on your report and it works out ApoB/ApoA1 as you type, in your browser.
AI-verified against cited sources. Awaiting expert reviewLast reviewed 2026-10-03Heart & Cholesterol
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Educational information, not medical advice. Blood Test Tracker doesn’t diagnose or treat, and it doesn’t replace your clinician. Talk with your clinician before changing medications, supplements or care.
How it’s worked out
The formula
ApoB / ApoA1, with both values in the same unit (for example mg/dL or g/L). The unit cancels, so the ratio is the same number in either unit.
A worked example
Example numbers, not anyone’s real results, run through the same code as the calculator above.
| ApoB | 80 mg/dL |
|---|---|
| ApoA1 | 150 mg/dL |
| ApoB/ApoA1 | 0.53 ratio |
What ApoB/ApoA1 tells you
The ApoB/ApoA1 ratio divides your ApoB result by your ApoA1 result, both in the same unit. ApoB is the protein on the cholesterol-carrying particles that can build up in artery walls, such as LDL and VLDL. ApoA1 is the main protein on HDL, the particles that help carry cholesterol away. The ratio puts the two sides into one number. Because the units cancel, it is the same number whether the labs report mg/dL or g/L.
In large studies, people with a higher ApoB/ApoA1 ratio had more heart attacks. In INTERHEART, a study of heart attacks in 52 countries, the odds were about 3.3 times higher in the top fifth of the ratio than in the bottom fifth. In AMORIS, a study of more than 175,000 people, the ratio was strongly linked to deaths from heart attack in both men and women. The 2018 US cholesterol guideline summary mentions ApoB but not this ratio, so clinicians use it as extra context rather than a target.
Read the full page on ApoB/ApoA1, with what a high or low result can mean.
Usual ranges
The ranges the result above is placed on. Your own lab’s printed range comes first if it gives one.
- Menup to 0.9 ratio
Sources: Mayo Clinic Laboratories (Extended Catalog), ARUP Laboratories
- Womenup to 0.8 ratio
Sources: Mayo Clinic Laboratories (Extended Catalog), ARUP Laboratories
Sources
The equation
- Apolipoprotein A1 and B, Serum (test APOAB), including the Apolipoprotein B/A1 ratio, Mayo Clinic Laboratories (Extended Catalog)
- Apolipoprotein B/A Ratio (test 0050028), ARUP Laboratories
4 more sources for the ranges and the explanation
- Effect of potentially modifiable risk factors associated with myocardial infarction in 52 countries (the INTERHEART study): case-control study, The Lancet (2004)
- High apolipoprotein B, low apolipoprotein A-I, and improvement in the prediction of fatal myocardial infarction (AMORIS study): a prospective study, The Lancet (2001)
- 2018 AHA/ACC/AACVPR/AAPA/ABC/ACPM/ADA/AGS/APhA/ASPC/NLA/PCNA Guideline on the Management of Blood Cholesterol: Executive Summary, Circulation (2019)
- Apolipoprotein A-1, Pathology Tests Explained (Royal College of Pathologists of Australasia) (2025)
AI-verified against cited sources. Awaiting expert review. Last reviewed 2026-10-03. The calculator is version 1.0.0 of our code for this equation, tested against published examples. How we build and check these pages.