Ability of the multiple-breath washout test to detect the presence of neutrophil elastase, respiratory infections and structural lung disease in pre-school children with cystic fibrosis who achieved three or more and two or more acceptable trials
| Lung clearance index | First moment ratio | Second moment ratio | ||||
| Three or more acceptable trials | Two or more acceptable trials | Three or more acceptable trials | Two or more acceptable trials | Three or more acceptable trials | Two or more acceptable trials | |
| Neutrophil elastase | ||||||
| Sensitivity % | 83 (59–96) | 83 (59–96) | 89 (65–99) | 89 (65–99) | 89 (65–99) | 89 (65–99) |
| Specificity % | 61 (43–76) | 64 (46–79) | 61 (43–76) | 64 (46–79) | 47 (31–64) | 47 (30–65) |
| Respiratory infection | ||||||
| Sensitivity % | 67 (43–85) | 70 (47–87) | 67 (43–85) | 74 (54–87) | 71 (48–89) | 83 (63–93) |
| Specificity % | 58 (39–75) | 56 (38–72) | 58 (39–75) | 53 (37–68) | 42 (25–61) | 42 (27–58) |
| Bronchiectasis | ||||||
| Sensitivity % | 66 (46–82) | 70 (51–85) | 65 (46–82) | 69 (50–84) | 83 (64–94) | 84 (67–95) |
| Specificity % | 59 (33–82) | 69 (41–89) | 59 (33–82) | 63 (35–85) | 53 (28–77) | 63 (35–85) |
Data are presented as median (range).