TABLE 1.

Sensitivity and specificity of fractional exhaled nitric oxide (F_ENO) for diagnosing asthma from three studies

	FENO ppb	Sensitivity %	Specificity %
Murray et al. [39]	≥24#	63#	73#
	≥35	52	83
	≥40	46	87
De Jong et al. [38]	≥20	52	77
	≥21	50	80
	≥23	48	87
	≥25#	46#	88#
ERS task force [29]	>15	75	61
	>20	58	68
	>25#	57#	81#
	>30	44	79
	>35	36	81

The study by Murray et al. [39] was based on a population not selected for asthma, whereas the remaining studies used data from children referred to hospital with possible asthma. ERS: European Respiratory Society. ^#: at values of 24 or 25 ppb, the sensitivity of F_ENO is lower and the specificity is higher for children at a higher risk of asthma compared to children in the general population.