Table 2– Comparison of nasal nitric oxide (nNO) levels (ppb) between primary ciliary dyskinesia (PCD),cystic fibrosis (CF) and healthy nonsmoking subjects (HS) in the three sampling methods

	HS	PCD	CF	p-value^#	p-value^¶
BH-nNO	908±33 (49)	142±42 (45)	416±28 (45)	<0.0001	<0.0001
OE-R-nNO	788±41 (30)	113±42 (35)	412±76 (10)	<0.0001	<0.01
TB-nNO	534±30 (52)	86±28 (54)	243±39 (17)	<0.0001	<0.01

Data are presented as mean±se (n), unless otherwise stated. BH-nNO: breath hold nNO; OE-R-nNO: oral exhalation against resistance nNO; TB-nNO: tidal breathing nNO. ^#: PCD versus HC; ^¶: PCD versus CF.