Interpreting FeNO

Measuring FeNO helps Healthcare Providers to optimize the use of steroids.¹

Determining Responsiveness to Anti-inflammatory Therapy

An important benefit of measuring fractional exhaled nitric oxide (FeNO) is its ability to identify patients who are likely to benefit from treatment with corticosteroids.¹

It has been shown that FeNO predicts the likelihood of steroid responsiveness more consistently than spirometry, bronchodilator response, peak flow variation, or airway hyperresponsiveness to methacholine.^2-4

Overview of Clinical Guideline to Interpretation of FeNO Levels¹

For the management of patients with suspected or diagnosed asthma

	FeNO-GUIDED THERAPY GOAL RANGE
FeNO levels and inflammation
FeNO (ppb)*	LOW	INTERMEDIATE	HIGH
Adults	<25	25-50	>50
Children (<12 years)	<20	20-35	>35
Th2-driven inflammation	Unlikely	Likely	Significant
Diagnosis Considerations
Interpretation with respect to steroid response	Unlikely to respond to corticosteroids	May respond to corticosteroids (interpret cautiously in clinical context)	Highly likely to respond to corticosteroids
Guide to diagnosis	Consider alternative diagnosis including chronic cough, vocal cord dysfunction, non-allergic asthma, GERD	Be cautious, but consider asthma Monitor change in FeNO over time	Supports a diagnosis of asthma
Monitoring (in patients with diagnosed asthma)
Symptoms present	Consider alternative diagnosis Not likely to respond to increased ICS dose Consider rechecking in 2-3 months	Consider persistent allergen exposure Check adherence Consider increasing ICS dose Consider steroid resistance Consider rechecking in 2-3 months	Consider persistent allergen exposure Check adherence and inhaler technique Consider increasing ICS dose Consider other anti-inflammatory therapy Consider rechecking in 2-4 weeks
Symptoms absent	Adequate ICS dose Good adherence If on ICS, consider decreasing dose or discontinuing ICS Consider rechecking in 2-4 weeks	Adequate ICS dosing Good adherence Monitor change in FeNO Consider rechecking in 2-3 months	ICS withdrawal or dose reduction may result in relapse Poor adherence or inhaler technique Consider rechecking in 2-3 months

*Interpretations of levels based on patient having symptoms (cough and/or wheeze and/or shortness of breath) present during the past 6+ weeks. Smoking has been shown to reduce FeNO levels.⁵

Learn more about updated FeNO monitoring guidelines Read about a patient with chronic cough

Interpreting FeNO

Measuring FeNO helps Healthcare Providers to optimize the use of steroids.1

Determining Responsiveness to Anti-inflammatory Therapy

Overview of Clinical Guideline to Interpretation of FeNO Levels1

For the management of patients with suspected or diagnosed asthma

Measuring FeNO helps Healthcare Providers to optimize the use of steroids.¹

Overview of Clinical Guideline to Interpretation of FeNO Levels¹