Table 4.

—Value of Feno in Predicting the Need for Acute Medical Attention for Asthma Over 3 Mo (One Visit) Stratified by Age

	Hospitalization		ED Visit		Unscheduled Doctor Visit		Any Acute Visit
Feno, ppb	PPV, %	NPV, %	PPV, %	NPV, %	PPV, %	NPV, %	PPV, %	NPV, %
Age < 12 y
Lowa	0	100	19.4	77.3	24.3	82.0	33.0	65.3
Highb	0	100	23.6	80.3	22.6	81.0	39.6	70.1
Age ≥ 12 y
Lowa	1.2	96.6	11.9	85.5	14.3	92.4	25.0	77.9
Highb	6.2	99.3	13.6	86.5	7.4	88.5	23.5	77.0

See Table 1 and 3 legends for expansion of abbreviations.

^aFeno < 20 ppb for those aged < 12 y and < 25 ppb for those ≥ 12 y.

^bFeno > 35 ppb for those aged < 12 y and > 50 ppb for those ≥ 12 y.