🫁 The FeNO Test: What It Means for People with Aspergillosis

If you have aspergillosis, particularly ABPA (Allergic Bronchopulmonary Aspergillosis) or overlapping asthma, your doctor might suggest a test called FeNO. But what is it—and is it useful for people like you?

This guide explains the FeNO test in simple terms, how it works in patients with aspergillosis, and what to expect from the results.

🔍 What Is the FeNO Test?

FeNO stands for Fractional Exhaled Nitric Oxide. It’s a quick and painless breathing test that measures the level of nitric oxide gas in your breath.

Nitric oxide is naturally produced in your lungs. When your airways are inflamed—especially with eosinophilic (type 2) inflammation—levels go up.

This kind of inflammation is common in:

• Asthma

• Allergic Bronchopulmonary Aspergillosis (ABPA)

• Some cases of chronic aspergillosis with allergic features

🎯 Why Might Aspergillosis Patients Be Offered a FeNO Test?

Your team might use FeNO to:

• Support a diagnosis of ABPA or allergic asthma

• Monitor inflammation levels over time

• Check if inhaled steroids are working

• Help plan changes to your treatment

FeNO can help show how much inflammation is active in your lungs, even if your symptoms haven’t changed much.

📈 Is the FeNO Test Accurate?

FeNO is a proven and recommended tool in asthma and allergic lung disease, including ABPA. But it works best when used alongside other information—such as:

• Blood tests (like total and specific IgE)

• CT scans

• Lung function tests

• Sputum cultures and fungal markers

So FeNO doesn’t give a “yes” or “no” answer by itself. It’s part of the bigger picture.

⚠️ What Can Affect the Results?

Certain things can raise or lower your FeNO level:

• Smoking (lowers it)

• Recent steroid use (lowers it)

• Recent infections

• Foods rich in nitrates (like beetroot, spinach)

• ABPA flares (may raise it)

This is why your clinician will always interpret your FeNO result in context.

🩺 Should You Trust It?

Yes — when interpreted by an experienced team, FeNO is a safe and useful tool. It helps in understanding how allergic inflammation behaves in your lungs, especially if you’re living with ABPA or asthma alongside aspergillosis.

✅ Summary for Aspergillosis Patients

• FeNO is helpful in allergic forms of aspergillosis, like ABPA

• It measures airway inflammation, especially type 2 (eosinophilic) inflammation

• It helps guide treatment with inhaled steroids or biologics

• It’s not a stand-alone test—it’s used together with other clinical information

• If you’re unsure what your FeNO result means, just ask your care team

If you’re being treated at the National Aspergillosis Centre, or referred for specialist care, FeNO testing may be used to help plan or fine-tune your treatment.