How new diagnostic technologies may improve detection of Aspergillus lung infections
Last reviewed: March 2026
Author: Graham Atherton
Key points
- Diagnosing Aspergillus lung infections can be challenging because symptoms often resemble other lung diseases.
- Doctors usually combine CT scans, blood tests and microbiology tests to make a diagnosis.
- Researchers are developing new diagnostics that detect fungal DNA, fungal molecules, or drug-resistant strains.
- Emerging tools include PCR tests, antigen detection, rapid tests, sequencing technologies and artificial intelligence imaging.
- This page focuses on Aspergillus infections rather than allergic conditions such as Allergic Bronchopulmonary Aspergillosis, Severe Asthma with Fungal Sensitisation, or Aspergillus bronchitis.
- Many of these newer technologies are being studied in clinical trials and research programmes worldwide.
Table of contents
- 1. Important note: infection vs allergy
- 2. Why better diagnostics are needed
- 3. How Aspergillus infections are diagnosed today
- 4. Detecting the immune response vs detecting the fungus
- 5. Simple diagram: two ways of looking for Aspergillus disease
- 6. DNA testing (PCR diagnostics)
- 7. Fungal antigen detection
- 8. Rapid diagnostic tests
- 9. Breath diagnostics
- 10. Sequencing technologies and the lung microbiome
- 11. Detecting antifungal resistance
- 12. Artificial intelligence and CT imaging
- 13. Flowchart: how doctors diagnose chronic Aspergillus infection
- 14. The future diagnostic pathway
- 15. Common questions patients ask
- 16. When to seek medical advice
- 17. References
1. Important note: infection vs allergy
This article focuses on diagnosing Aspergillus infections of the lungs, particularly:
- Chronic Pulmonary Aspergillosis
- Aspergillus nodules
- Aspergilloma (fungal ball)
- Subacute invasive aspergillosis
These conditions involve the fungus growing in lung tissue or in pre-existing lung cavities.
This is different from allergic Aspergillus disease, such as:
- Allergic Bronchopulmonary Aspergillosis (ABPA)
- Severe Asthma with Fungal Sensitisation (SAFS)
- Aspergillus bronchitis (which overlaps with airway disease rather than the classic cavity-forming infections discussed here)
In allergic disease, diagnosis focuses more on immune reactions, such as IgE antibodies, eosinophils, allergy testing and markers of Type 2 inflammation.
This page therefore focuses mainly on diagnostics for Aspergillus infection rather than allergy. A separate article can cover immune diagnostics in allergic Aspergillus disease.
2. Why better diagnostics are needed
Chronic Pulmonary Aspergillosis often develops in people who already have damaged lungs, for example from:
- tuberculosis
- Chronic Obstructive Pulmonary Disease
- bronchiectasis
- sarcoidosis
- previous severe lung infections
- lung surgery
Symptoms may include:
- chronic cough
- breathlessness
- fatigue
- weight loss
- coughing up blood
- chest discomfort
These symptoms are not specific, meaning they can occur in many other lung diseases.
Aspergillus is also very common in the environment, so detecting it in sputum does not always mean it is causing disease. Sometimes it may simply be present without invading tissue or causing progressive damage.
For these reasons, diagnosing chronic aspergillosis usually requires multiple tests interpreted together, rather than relying on one result alone.
3. How Aspergillus infections are diagnosed today
Doctors usually combine three main types of evidence.
| Diagnostic method | What it shows |
|---|---|
| CT scan | Structural lung changes such as cavities, nodules or fungal balls |
| Blood tests | The body’s immune response to Aspergillus |
| Microbiology tests | Evidence of the fungus itself |
The most important blood test for many patients with Chronic Pulmonary Aspergillosis is Aspergillus IgG antibodies.
CT scans are also critical because they can reveal features such as:
- lung cavities
- fungal balls
- nodules
- thickened cavity walls
- progressive lung destruction or scarring
Microbiology may include sputum culture, bronchoscopy samples, microscopy, molecular testing and antigen detection.
No single test is perfect. Doctors usually look at the whole picture: symptoms, scan findings, blood tests, microbiology, and how things change over time.
4. Detecting the immune response vs detecting the fungus
Some diagnostic tests detect how the body reacts to Aspergillus, while others try to detect the fungus itself.
Immune response tests
Examples include:
- Aspergillus IgG antibodies
- general inflammatory markers
These tests show that the immune system has encountered Aspergillus, but they do not always prove that the fungus is currently active, growing, or causing ongoing damage.
Direct fungal detection
Other tests look for components of the fungus itself.
| Test | What it detects |
|---|---|
| PCR | Aspergillus DNA |
| Galactomannan | Fungal cell wall molecules |
| Beta-D-glucan | Fungal structural components |
| Culture | Growth of the fungus in the laboratory |
These tests can sometimes provide more direct evidence that fungal material is present.
Why not rely only on the immune response?
Immune-response tests are extremely useful, but they are indirect. They tell us what the body is doing, not necessarily what the fungus is doing at that moment.
Antibodies may remain raised for quite a long time, may change only slowly, and may vary from person to person. Some patients also produce weaker immune responses than others.
By contrast, tests that detect fungal DNA or fungal cell wall components may sometimes give a better sense that fungal material is actually present in the lungs.
The footprints analogy
A useful way to understand this difference is:
- Immune response tests are like seeing footprints in the snow – they show that someone has been there.
- Direct fungal tests are like seeing the person themselves – they show that the organism is present.
In practice, doctors usually combine both kinds of evidence to make the diagnosis more reliable.
5. Simple diagram: two ways of looking for Aspergillus disease
Two broad diagnostic approaches
| Approach | Examples | Main question |
|---|---|---|
| Looking for the body’s response | Aspergillus IgG, inflammation markers | Has the immune system reacted to Aspergillus? |
| Looking for the fungus itself | PCR, galactomannan, Beta-D-glucan, culture | Is fungal material present? |
| Looking for damage caused in the lungs | CT scan | Has Aspergillus or another disease caused structural lung change? |
This is why diagnosis is usually based on a combination of evidence rather than any single test.
6. DNA testing (PCR diagnostics)
Polymerase Chain Reaction, usually shortened to PCR, detects the DNA of Aspergillus fungi.
These tests can be performed on samples such as:
- sputum
- bronchoscopy samples
- lung tissue
Advantages of PCR include:
- faster results than fungal culture
- detection of very small amounts of fungus
- possible detection even when cultures are negative
However, PCR also has challenges. It may detect fungal material even when it is not clearly causing disease, and methods are not yet fully standardised across all laboratories.
Even so, PCR is one of the most important emerging tools in fungal diagnostics and is increasingly used in specialist centres.
7. Fungal antigen detection
Some tests look for molecules released by fungal cells. These are often called antigen tests.
Galactomannan
Galactomannan is a molecule found in the cell wall of Aspergillus.
It is already widely used in diagnosing invasive aspergillosis and is being studied more closely in chronic forms of disease as well.
Beta-D-glucan
Beta-D-glucan is a structural component found in the cell walls of many fungi.
Raised levels can suggest fungal infection somewhere in the body, although it is not specific for Aspergillus alone.
Researchers are interested in how these markers might be used alongside CT, antibody testing and PCR to improve accuracy.
8. Rapid diagnostic tests
Researchers are also developing rapid antigen tests that can detect fungal molecules within minutes.
These tests work in a similar way to a simple strip test and may offer:
- quick results
- minimal laboratory equipment
- possible use in clinics with fewer resources
These tests are promising, but they still need careful evaluation to show how accurate and reliable they are in real patients with chronic Aspergillus disease.
9. Breath diagnostics
Fungi release small chemicals called volatile organic compounds. Some experimental devices aim to detect these compounds in exhaled breath.
If successful, breath testing could provide:
- completely non-invasive testing
- rapid screening
- repeat testing over time without invasive procedures
This remains an early and experimental field, but it is attractive because it could make testing much easier for patients.
10. Sequencing technologies and the lung microbiome
Modern sequencing technologies can analyse all microbial DNA in a sample.
This means they may identify:
- fungi
- bacteria
- viruses
These approaches may help doctors understand mixed infections and the broader lung microbiome, especially in people with bronchiectasis or complex chronic lung disease.
In the future, sequencing may help explain why some patients have persistent symptoms or repeated flares involving more than one organism.
11. Detecting antifungal resistance
Some strains of Aspergillus fumigatus have developed resistance to azole antifungal drugs.
Newer diagnostic tests can detect genetic mutations linked to drug resistance, especially in the CYP51A gene.
Earlier detection of resistance could help doctors:
- choose effective antifungal drugs sooner
- avoid ineffective treatment
- improve long-term outcomes
This is an important area of research because antifungal resistance is a growing international concern.
12. Artificial intelligence and CT imaging
Artificial intelligence is increasingly being explored as a way to analyse CT scans more precisely.
These systems may eventually help doctors:
- detect subtle lung changes earlier
- measure cavity size or progression more consistently
- monitor disease over time
- compare scans more accurately
Artificial intelligence is unlikely to replace expert radiologists or specialist teams, but it may become a useful support tool.
13. Flowchart: how doctors diagnose chronic Aspergillus infection
Typical diagnostic pathway
Symptoms
persistent cough, breathlessness, fatigue, weight loss, coughing up blood
↓
CT scan
looking for cavities, fungal balls, nodules, scarring or progressive damage
↓
Blood tests
especially Aspergillus IgG and general inflammatory markers
↓
Microbiology
sputum, bronchoscopy, culture, PCR, antigen tests
↓
Clinical interpretation
combining symptoms, imaging, blood tests and microbiology
↓
Diagnosis and follow-up
deciding whether this is infection, colonisation, another lung condition, or mixed disease
This flowchart is simplified, but it shows the basic principle: diagnosis depends on combining evidence.
14. The future diagnostic pathway
In the future, diagnosing Aspergillus infection may involve several rapid tests used together.
A possible pathway could look like this:
Symptoms → CT scan → fungal antigen test → PCR confirmation → resistance testing
This approach could allow:
- faster diagnosis
- more personalised treatment
- earlier detection of complications
- better treatment monitoring
The aim is not necessarily to replace older tests, but to make the whole diagnostic process earlier, clearer and more precise.
15. Common questions patients ask
Why can Aspergillus infection take time to diagnose?
Because no single test can confirm the disease on its own. Doctors usually need to combine scan findings, blood tests, microbiology and the clinical history.
Why do some tests detect antibodies while others detect the fungus?
Antibody tests show how the immune system has reacted. Molecular and antigen tests try to show whether fungal material is present. Both are useful, but they answer slightly different questions.
Why is a CT scan so important?
A CT scan shows whether there is structural lung damage such as cavities, nodules or fungal balls. This helps doctors judge whether Aspergillus is likely to be causing disease rather than simply being present.
Are these new diagnostics available now?
Some are already used in specialist centres, but many are still being evaluated in clinical trials and research studies.
Will these newer tests replace existing blood tests?
Probably not completely. More likely, they will be used alongside existing tests to improve accuracy and speed.
16. When to seek medical advice
You should seek medical advice if you have symptoms such as:
- persistent cough
- worsening breathlessness
- unexplained fatigue
- weight loss
- coughing up blood
- new or worsening chest pain
These symptoms can have many causes, but they should be assessed properly, especially if you already have underlying lung disease.
17. References
- Denning DW, Cadranel J, Beigelman-Aubry C, Ader F, Chakrabarti A, Blot S, Ullmann AJ, Dimopoulos G, Lange C; European Society for Clinical Microbiology and Infectious Diseases and European Respiratory Society. Chronic pulmonary aspergillosis: rationale and clinical guidelines for diagnosis and management. Eur Respir J. 2016 Jan;47(1):45-68. doi: 10.1183/13993003.00583-2015. PMID: 26699723.
- Kosmidis C, Denning DW. The clinical spectrum of pulmonary aspergillosis. Thorax. 2015 Mar;70(3):270-7. doi: 10.1136/thoraxjnl-2014-206291. Epub 2014 Oct 29. PMID: 25354514.
- Takazono T, Izumikawa K. Recent Advances in Diagnosing Chronic Pulmonary Aspergillosis. Front Microbiol. 2018 Aug 17;9:1810. doi: 10.3389/fmicb.2018.01810. PMID: 30174658; PMCID: PMC6107790.
Author and review information
This page is intended for patients, carers, and non-specialist clinicians. It provides general educational information and should not replace individual medical advice.
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