Success rates of obtaining acceptable and repeatable multiple-breath washout measurements in pre-school-aged children when three or more trials or two or more trials were deemed acceptable
| Age years | Cystic fibrosis | Healthy | ||
| Three or more acceptable trials | Two or more acceptable trials | Three or more acceptable trials | Two or more acceptable trials | |
| 3 | 7/21 (33) | 14/21 (67)* | 10/14 (71) | 13/14 (93) |
| 4 | 18/38 (47) | 27/38 (71)* | 9/17 (53) | 15/17 (88)* |
| 5 | 22/49 (45) | 35/49 (71)** | 14/26 (54) | 22/26 (85)* |
| 6 | 28/41 (68)* | 9/15 (60) | 11/15 (73) | |
| Overall | 66/149 (44) | 104/149 (70)*** | 42/72 (58) | 61/72 (85)*** |
Data are presented as n/N (%). The Chi-squared test was used to compare differences in proportions between visits with three or more acceptable trials and two or more acceptable trials. *: p<0.05; **: p<0.01; ***: p<0.001.