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Calculates the apolipoprotein B to apolipoprotein A1 ratio (ApoB:ApoA1), an index of the balance between atherogenic (ApoB) and anti-atherogenic (ApoA1) lipoproteins used in cardiovascular risk assessment.
ApoB:ApoA1 = ApoB (g/L) ÷ ApoA1 (g/L)
Male: 0.3–1.0 (ratio 1.0 as a general upper reference); Female: 0.3–0.8
ApoB is present on all atherogenic lipoproteins (LDL, VLDL, IDL, Lp(a)) while ApoA1 is the main protein of HDL. The ApoB:ApoA1 ratio summarizes the atherogenic-to-protective balance and has been studied in large cohorts such as INTERHEART.
Specialty
Internal MedicineCategory
LaboratoryDifficulty
Basic
Estimated Time
30 seconds
Version
1.0
Last Updated
2026-08-16
Formula
Keywords
Normal Range
Male: 0.3–1.0 (ratio 1.0 as a general upper reference); Female: 0.3–0.8
| Classification | Range |
|---|---|
Male reference range Male · typical laboratory reference interval | 0.30–1.00 |
Female reference range Female · typical laboratory reference interval | 0.30–0.80 |
Elevated (increased risk) cardiovascular risk marker | >1.0 (male) / >0.8 (female) |
Calculates the apolipoprotein B to apolipoprotein A1 ratio (ApoB:ApoA1), an index of the balance between atherogenic and anti-atherogenic lipoproteins used in cardiovascular risk assessment.
The typical reference range is 0.30–1.00 in men and 0.30–0.80 in women. A ratio above 1.0 (men) or 0.8 (women) is elevated and associated with higher cardiovascular risk. Thresholds are population conventions; use the performing laboratory's reference interval when available.
ApoB counts the number of atherogenic particles while ApoA1 reflects the protective HDL fraction, making their ratio a strong cardiovascular risk marker studied in large cohorts such as AMORIS and INTERHEART.
A 45-year-old man has an ApoB of 1.0 g/L and an ApoA1 of 1.4 g/L.
Inputs:
ApoB:ApoA1 = 1.0 ÷ 1.4 ≈ 0.71. This value is within the male reference range (0.30–1.00).
It reflects the balance between atherogenic and protective lipoproteins, and in epidemiological studies (e.g., INTERHEART, AMORIS) it has performed well as a cardiovascular risk marker.
LDL cholesterol measures cholesterol mass; ApoB counts the number of atherogenic particles (one per particle), which better captures risk from small, dense LDL and remnant particles.
Disclaimer: This calculator is intended for educational and clinical decision support purposes only. Use the performing laboratory's reference interval and incorporate the ratio into a complete cardiovascular risk assessment.