ApoB (≥130 mg/dL) — ASCVD Risk
Test Characteristics
| Metric | Value |
|---|---|
| False-negative rate | 26% (sensitivity 74%) |
| False-positive rate | 17% (specificity 83%) |
| Bayes factor (positive test) | 5× |
| Bayes factor (negative test) | 1/3× |
| Base rate | 7.5% 10-year ASCVD risk (borderline-risk patients) |
Interpreting Results
| Scenario | Prior | + Result | − Result |
|---|---|---|---|
| Borderline risk (5–7.5% 10-yr ASCVD) | 7.5% | 5 × 7.5% = 37.5%7.5%× 537.5% | 1/3 × 7.5% = 2.5%7.5%÷ 32.5% |
| Intermediate risk (7.5–20% 10-yr ASCVD) | 15% | 5 × 15% = 75%15%× 575% | 1/3 × 15% = 5%15%÷ 35% |
Like the CAC score, ApoB works best as a risk reclassifier — moving patients between risk categories — rather than a traditional diagnostic test. The Bayes factor framework is a rough fit. ApoB ≥130 mg/dL corresponds to roughly the 90th percentile and is a risk-enhancing factor per AHA/ACC guidelines. ApoB outperforms LDL-C in predicting ASCVD events, especially when LDL and ApoB are discordant (normal LDL but elevated ApoB). Most useful in borderline/intermediate-risk patients where the statin decision is uncertain.
- + result: risk goes from borderline (7.5%) to 37.5% — strong signal for statin initiation
- − result: risk drops to red hair (2.5%) — modest reassurance
Sources:
- AHA/ACC. ApoB: bridging the gap between evidence and clinical practice.
- National Lipid Association. Role of ApoB in clinical management.
- PMC. ApoB — an ideal biomarker for atherosclerosis?.