NT-proBNP — Heart Failure
Test Characteristics
| Metric | Value |
|---|---|
| False-negative rate | 10% (sensitivity 90%) |
| False-positive rate | 16% (specificity 84%) |
| Bayes factor (positive test) | 5× |
| Bayes factor (negative test) | 1/10× |
| Base rate | 2% of adults in primary care |
Interpreting Results
| Scenario | Prior | + Result | − Result |
|---|---|---|---|
| Unselected primary care patient | 2% | 5 × 2% = 10%2%× 510% | 1/10 × 2% = 0.2%2%÷ 100.2% |
| Dyspnea, edema, and orthopnea | 20% | 5 × 20% ≥ 100%20%× 5100% | 1/10 × 20% = 2%20%÷ 102% |
5 × 20% ≥ 100%20%× 5100%: exact posterior is 56%. Age-related cutoffs: 450, 900, and 1800 pg/mL for ages <50, 50–75, and >75.
- + result: risk goes from red hair (2%) to left-handed (10%)
- − result: risk drops to near identical twin (0.2%)
Sources:
- International pooled analysis of 1,256 patients, 2006. European Heart Journal.