Positive predictive value of specific components of diagnostic protocol (using successful response to therapy as the outcome)
| Test | No. of positive tests | No. responding to relevant treatment | Positive predictive value (%) |
|---|---|---|---|
| Histamine challenge | 17 | 15 | 88 |
| 24 h oesophageal pH monitoring | 19 | 13 | 68 |
| ENT examination | 16 | 10 | 63 |
| CT scan sinuses | 18 | 12 | 67 |
ENT = ear, nose and throat; CT = computed tomography.