TABLE 2.

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.