Exhaled Nitric Oxide as a Biomarker in COPD and Related Comorbidities

Table 1

Trend of FeNO levels in COPD and related comorbidities.

Disease/condition	FeNO levels
Smoking habit	↓
Severe COPD	↓
Stable COPD	=
Exacerbation of COPD	↑
AAT deficiency PiZZ	↓
AAT deficiency PiMZ	↑
PAH	↓
Systemic sclerosis	↑
Decompensated HF	↑
After exercise in stable HF	↑
Atherosclerosis	↓
Psoriasis	↑

↑: >20 ppb; =: 10–20 ppb; ↓: <10 ppb.