FeNO does not diagnose asthma alone. It is interpreted with symptoms, examination, lung function, allergy history and treatment use.

Emergency note
Do not wait online for emergency breathing signs.

Severe breathing difficulty, chest indrawing, blue lips, drowsiness, poor feeding, grunting, pauses in breathing, persistent fast breathing, low oxygen — these are not for online review. Go to in-person pediatric emergency care.

Original self-explanatory visual. FeNO measures nitric oxide in exhaled breath. It is one clue, not the whole diagnosis. This image was created for Together. We. Breathe. and does not reproduce any textbook or guideline figure.
Original self-explanatory visual. FeNO measures nitric oxide in exhaled breath. It is one clue, not the whole diagnosis. This image was created for Together. We. Breathe. and does not reproduce any textbook or guideline figure.

What parents usually notice.

Common reasons doctors think about.

What a pediatric pulmonologist checks.

What not to do blindly.

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