Beyond Asthma : The Clinical Versatility of FeNO Testing
What is FeNO? Fractional exhaled Nitric Oxide (FeNO) is a non-invasive biomarker used to detect, monitor, and screen airway inflammation across a wide range of conditions — not just asthma.
Relevance to Asthma (Core Application)
While the infographic highlights FeNO’s versatility, its asthma-related utility remains central:
- Monitoring Treatment Response — FeNO helps assess a patient’s adherence to inhaled corticosteroids (ICS) and guides ongoing steroid therapy decisions. Elevated FeNO in a patient on ICS may signal poor adherence or inadequate dosing.
- Eosinophilic Inflammation — Elevated FeNO levels indicate eosinophilic airway inflammation, which directly guides anti-inflammatory treatment choices in asthma management.
- Steroid-Responsive Phenotyping — In overlapping conditions like COPD, FeNO helps identify patients whose inflammatory profile resembles asthma and are likely to benefit from corticosteroids.
Broader Clinical Versatility
| Condition | FeNO Characteristic | Clinical Value |
|---|---|---|
| Eosinophilic Inflammation | Elevated | Guides anti-inflammatory therapy |
| COPD & Chronic Cough | Variable | Identifies steroid-responsive phenotypes |
| Primary Ciliary Dyskinesia | Very low/Absent | Supports PCD diagnosis |
| Allergic/Atopic Conditions | Elevated | Detects eosinophilic inflammation in rhinitis & dermatitis |
| Occupational Screening | Variable | Screens for occupational asthma |
| Systemic Research | Variable | Links to hypertension & diabetes |
Key Takeaway
FeNO is most established as an asthma management tool — particularly for guiding steroid therapy and confirming eosinophilic inflammation — but its utility is expanding into occupational health, rare diseases like PCD, and systemic disease research, making it a highly versatile non-invasive clinical tool.
