Diagnostic value of isolated symptoms
| Symptom | S% | SP% | PPV% | NPV% | J |
| Wheezing | 74.7 | 87.3 | 12.4 | 99.3 | 0.62 |
| Wheezing with dyspnoea | 65.2 | 95.1 | 23.9 | 99.1 | 0.6 |
| Wheezing without cold | 59.8 | 93.6 | 18.2 | 99 | 0.53 |
| Nocturnal chest tightness | 49.3 | 86.4 | 8 | 98.6 | 0.36 |
| Rest dyspnoea | 47.1 | 94.9 | 18 | 98.7 | 0.42 |
| Exercise dyspnoea | 69.3 | 75.7 | 6.4 | 99 | 0.45 |
| Nocturnal dyspnoea | 46.2 | 96 | 21.5 | 98.7 | 0.42 |
| Nocturnal cough | 49.3 | 72.3 | 4.1 | 98.4 | 0.22 |
| Chronic cough | 21.5 | 95.2 | 9.6 | 98.1 | 0.17 |
| Chronic phlegm | 22.7 | 93.3 | 7.5 | 98.1 | 0.16 |
| Chronic bronchitis | 12.5 | 98.2 | 14 | 97.9 | 0.11 |
S: sensitivity; SP: specificity; PPV: positive predictive value; NPV: negative predictive value; J: Youden index.