🧪 Understanding Blood Tests in ABPA-S

How Aspergillus-specific IgE and Eosinophil Counts Help with Diagnosis

If you’ve been told you might have Allergic Bronchopulmonary Aspergillosis – Serologic type (ABPA-S), you’ve probably had blood tests measuring your Aspergillus-specific IgE and your eosinophil count. These markers help doctors understand whether your immune system is reacting unusually to a common fungus called Aspergillus fumigatus.

This article explains what those tests mean — and why normal results don’t always rule out ABPA-S.

🌾 What is Aspergillus-specific IgE?

This blood test checks whether your immune system is producing allergy antibodies (IgE) against Aspergillus fumigatus. High levels suggest that your body is reacting to this fungus — a key sign in ABPA.

What do the results usually look like in ABPA-S?

• Above 0.35 kUA/L – this is the minimum level needed for ABPA diagnosis

• Above 1.5–6.5 kUA/L – this is very common in ABPA-S

• Above 20 or even 50 kUA/L – these are often seen in more active or severe cases

🔍 Low or normal levels (below 0.35) are rare in ABPA-S unless:

• You are already receiving treatment

• You are in remission

• There was a problem with the test

• Your condition might be a different type of fungal allergy

So if your Aspergillus-specific IgE is high, that strongly supports the diagnosis. If it’s low, your doctor may retest or look at other factors.

🧬 What is an eosinophil count?

Eosinophils are a type of white blood cell linked to allergic inflammation. In many allergic conditions, including ABPA-S, these levels can go up.

What levels are typical in ABPA-S?

• Above 500 cells/µL – commonly seen in untreated or active ABPA-S

• Above 1,500 cells/µL – often seen in flare-ups

• Below 500 cells/µL – can occur in people with milder disease or if they’ve started treatment

🟡 Normal eosinophils are not rare in ABPA-S
Many people with ABPA-S — especially those already on steroids or antifungals — may have eosinophil levels in the normal range. Up to a third of people with ABPA-S may show normal counts at some point.

🩺 What This Means for You

So if your blood tests show:

• High Aspergillus-specific IgE → that strongly supports ABPA-S

• Normal eosinophils → this does not rule it out

💬 What patients often ask:

“Can I have ABPA-S with normal eosinophils?”

Yes. Especially if you’re already on steroids, or your symptoms are mild, your eosinophil count may appear normal.

“Does a low Aspergillus-specific IgE mean I don’t have ABPA?”

Not necessarily. Your doctor will consider your symptoms, scan results, and other blood tests too. Sometimes the test needs repeating.

🤝 Patient voices matter

If you’ve had these tests and been diagnosed with ABPA-S, sharing your experience can help others feel less alone — and more informed when navigating lab results.

Need help understanding your lab report?

Ask your care team:

• What was my Aspergillus-specific IgE level?

• What was my eosinophil count?

• Are these results typical for someone with ABPA-S like mine?

Understanding your blood tests can help you take more confident steps in managing your condition.