🩺 Lung Function Tests Explained: What They Tell Us About Asthma, COPD, Bronchiectasis, and Aspergillosis

If you’re living with a lung condition like asthma, COPD, bronchiectasis, or aspergillosis, you may be asked to have a lung function test. These tests help your medical team understand how well your lungs are working — and how best to treat you.

🌬️ What Are Lung Function Tests?

Lung function tests (also called pulmonary function tests) measure:

• How fast and deeply you can breathe

• How well your lungs move oxygen into your blood

• How much air gets trapped in your lungs

🔬 Main Tests and What They Measure

🧠 What Do These Tests Tell Us?

Here’s how different conditions show up in lung function testing:

🟢 Asthma

• Airways are narrowed, but often improve with inhalers.

• Shows obstruction that improves significantly after a bronchodilator (reversible).

• Lung volumes usually normal; DLCO often normal or high.

🔵 COPD

• Shows irreversible obstruction — lungs are stiff and narrowed.

• Often shows air trapping and hyperinflation.

• DLCO is reduced, especially in emphysema.

🟠 Bronchiectasis

• May show mild-to-moderate obstruction or mixed patterns.

• Sometimes reversible, depending on overlapping asthma or infection.

• Lung volumes and DLCO often normal unless CPA or emphysema is also present.

🟣 Aspergillosis

• ABPA: Like asthma — obstruction, often with reversibility, air trapping, high IgE and eosinophils.

• CPA: May cause a restrictive pattern (lower lung volumes) or reduced DLCO if fibrosis or cavities are present.

• Aspergillus bronchitis: May look like bronchiectasis with some obstruction.

💨 What Is Air Trapping?

Air trapping happens when you breathe in, but can’t get all the air back out. Some air stays stuck in the lungs.

Common in:

• Asthma

• ABPA

• Bronchiectasis

• COPD

🎈 What Is Hyperinflation?

Hyperinflation means your lungs are constantly overfilled with air — not just trapped temporarily, but stretched long-term.

Common in:

• Severe asthma

• Emphysema (COPD)

• ABPA (when uncontrolled)

📊 Summary Table

💬 Why These Tests Matter

• They help distinguish what’s causing your symptoms.

• They track whether treatment is working (inhalers, steroids, antifungals).

• They identify complications like scarring, cavities, or fungal infection.

• They help guide eligibility for biologic drugs or oxygen therapy.

📣 Ask Your Doctor:

• Have I had a bronchodilator response test?

• Do I have air trapping or hyperinflation?

• Should we test for Aspergillus (IgG, IgE, sputum)?

• Would a CT scan add helpful detail?

by GAtherton

🫁 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.

by GAtherton

🧪 Understanding Aspergillosis Blood Tests: IgE and IgG Explained

For patients in the UK and internationally

If you are living with aspergillosis, including forms such as chronic pulmonary aspergillosis (CPA), allergic bronchopulmonary aspergillosis (ABPA), or severe asthma with fungal sensitisation (SAFS), you may have had blood tests that measure how your immune system responds to Aspergillus, a common type of fungus.

This guide explains the role of these tests, why results may vary between hospitals, and what they mean for diagnosis and ongoing care.

🔬 What Are These Blood Tests?

✅ Total IgE

• Measures your body’s overall allergic response.

• Often raised in people with ABPA or SAFS, but also in asthma, eczema, and parasitic infections.

✅ Aspergillus-Specific IgE

• Detects allergic reaction specifically to Aspergillus fumigatus.

• Helps diagnose ABPA and SAFS.

✅ Aspergillus-Specific IgG

• Measures immune response to longer-term exposure to Aspergillus.

• Mainly used to help diagnose CPA, but can also support ABPA diagnosis.

📊 What Are the Normal Ranges?

📌 Total IgE Reference Ranges (UK Examples)

In ABPA, total IgE is usually > 500 kU/L, and sometimes exceeds 1000 kU/L.

📌 Aspergillus-Specific IgE: Positive Ranges

📌 Aspergillus-Specific IgG: Positive Ranges

The exact “positive” level depends on the test platform used by the lab. Always check which test was used when reviewing results.

🧪 Why Do Reference Ranges Differ Between Hospitals?

It’s common for different hospitals and countries to use slightly different tests and reference ranges. This is due to:

• Different brands or types of test kits (e.g. ImmunoCAP, Bordier, Serion, LDBio)

• Varying units of measurement

• Locally validated ranges based on the population

• Differences in clinical protocols or disease thresholds

For example, a test result of Aspergillus IgG at 38 mgA/L may be seen as positive in one hospital and borderline in another depending on which assay is used.

🧭 How These Tests Fit into Aspergillosis Diagnosis

🩺 Blood Tests Help Guide the Diagnosis, But Are Not Enough Alone

Diagnosis always depends on a combination of factors — not just a blood test.

🧩 Other Essential Parts of Diagnosis

Blood tests are just one piece of the puzzle. Doctors always interpret them alongside imaging, symptoms, and history.

🩺 What About Management?

Once diagnosed, managing aspergillosis involves more than just monitoring blood tests. Your care plan may include:

• Antifungal medication (e.g. itraconazole, voriconazole)

• Steroids or biologics (especially in ABPA)

• Physiotherapy to clear mucus

• Regular imaging (e.g. CT scans)

• Monitoring IgE/IgG over time

• Patient support for fatigue, emotional health, and quality of life

📋 Understanding Your Results: What Do They Mean?

When you receive blood test results like total IgE, Aspergillus-specific IgE, or Aspergillus-specific IgG, you may see a number alongside a reference range (sometimes called the “normal range”). This helps show whether your result is considered low, normal, or high in that specific laboratory.

🧾 Example:

❓ Is a Slightly High Result a Problem?

• A mild or borderline elevation does not automatically mean disease.

• Some people may have a raised IgE or IgG but no active symptoms or signs of aspergillosis.

• Other people with clear disease may have only modest rises in their test levels.

🔍 Important: Test results must always be interpreted in the context of your overall health, scan results, and symptoms.

✅ Let Your Doctor Guide You

It’s completely normal to feel uncertain or anxious about test results — especially if a number is just above the “normal range.” But:

• Let your doctor or specialist interpret the result as part of your whole clinical picture.

• They may repeat the test, combine it with a CT scan or lung function test, or monitor changes over time.

• Some test levels, like total IgE in ABPA, are tracked over months to see if treatment is working.

💬 Ask your doctor:
“How does this result fit in with my symptoms and scan findings?”

🧠 Final Takeaway

Blood tests like IgE and IgG are essential tools in diagnosing and managing aspergillosis, but they are only one part of the bigger picture. Imaging, symptoms, response to treatment, and even how you feel day-to-day are just as important.
Always ask for a copy of your results with reference ranges, and bring them to appointments.
And remember — a slightly raised result doesn’t always mean something is wrong. Your doctor is the best person to interpret it for you.

by GAtherton