Table 3: Use of FEF 25-75% to predict combined outcome (CO) of ventilatory limitation (VR ≤ 15%) & reduced exercise capacity; and low VR (≤ 15%) at peak exercise.
| FEF 25-75% predicted | Sensitivity CO | Specificity CO | Positive Predictive value CO | Negative Predictive value CO | Sensitivity VR ≤ 15% | Specificity VR ≤ 15% | Positive Predictive value VR ≤ 15% | Negative Predictive value VR ≤ 15% |
| ≤ 10 | 15% | 99% | 73% | 87% | 11% | 99% | 73% | 80% |
| ≤ 20 | 42% | 95% | 59% | 90% | 33% | 96% | 68% | 83% |
| ≤ 30 | 65% | 89% | 52% | 94% | 53% | 91% | 62% | 87% |
| ≤ 40 | 73% | 82% | 43% | 94% | 61% | 84% | 52% | 88% |
| ≤ 50 | 85% | 74% | 36% | 96% | 71% | 75% | 45% | 90% |