Table 3 2 × 2 table of spirometry for diagnosing airway obstruction in patients with COPD (n = 208; asthma patients with FEV1 <80% of predicted in general practice and in lung function laboratory excluded)
| Â | COPD | No COPD | Â |
|---|---|---|---|
Spirometry + | 44 | 26 | Â |
Spirometry - | 4 | 134 | Â |
| Â | Â | Â | 208 |
Pretest probability of having COPD 23% | |||
Pretest probability of not having COPD 77% | |||
Sensitivity | 92% (95%CI 80–97) | ||
Specificity | 84% (95%CI 77–89) | ||
PPV | 63% (95%CI 51–73) | ||
NPV | 97% (95%CI 93–99) | ||