Diagnosing primary ciliary dyskinesia: understanding the professional guidelines
Content Table
Introduction
Who is this document for and what is it about?
This document is for people with primary ciliary dyskinesia (PCD), their family and their carers. It explains the recommendations in the European Respiratory Society (ERS) and American Thoracic Society (ATS) guidelines specific to the diagnosis of PCD.
What are clinical guidelines?
Clinical guidelines are produced after a scientific process is used to gather the latest evidence on a condition. Guidelines also take into account the opinions of experts and the priorities of patients and carers who have experience of a condition. Clinical guidelines are written for healthcare professionals. They use them as a best practice document on how to diagnose, manage, and treat a condition.
What does this document include?
This document summarises the key points from the clinical guidelines on the diagnosis of PCD. It explains them in a way that is easier to understand for people who do not work in the medical field. It will explain what PCD is and the ERS and ATS’ recommended approach to diagnose the condition. By providing this information in an accessible way, this document aims to help people with PCD, their family, and their carers understand best practice for the diagnosis of PCD. This information includes the key tests involved as well as how each conclusion has been reached.
The ERS uses the GRADE approach to make recommendations. This system means that recommendations can be either in favour of or against an action, and they can be strong or conditional:
✅ Strong recommendation in favour of:
The benefits clearly outweigh the harms, and healthcare professionals should offer this option routinely.
🤔 Conditional recommendation in favour of:
The option may be a good choice for some people, but it depends on individual situations. Healthcare professionals should discuss this option and see if it is right for you.
❌ Strong recommendation against:
The harms clearly outweigh the benefits, and nearly everyone should avoid this option. Healthcare professionals should not routinely offer this option.
⚠️ Conditional recommendation against:
The option may cause more harm than benefit for many, but some people might still prefer it. Healthcare professionals may discuss this option with you to see if it is right for you.
❓No recommendation
The authors of the guideline were unable to make a recommendation.
What is PCD?
PCD is a rare genetic condition where tiny hair-like structures called ‘cilia’ do not move properly. Cilia are found in the airways, ears and sinuses and normally help move mucus and germs out of the lungs. When cilia do not work, mucus builds up, which can cause repeated infections and irritation over time.
PCD may affect people differently, though symptoms can include a wet, chesty cough, regular chest infections, sinus infections due to blocked or runny nose and ear infections leading to hearing problems. For many people living with PCD, repeated symptoms in the lungs and sinuses can lead to bronchiectasis and long-term‑ sinus problems.
PCD can also affect other parts of the body, including the reproductive system, making it harder for some men and women with PCD to have children (fertility problems). People with PCD are more likely to have a condition called situs inversus, where the heart or other organs are on the opposite side of the body. If the heart is affected, this can sometimes cause heart problems.
PCD is passed down through faulty genes, but many families are unaware of other relatives with the condition. It affects about one in 7,500 people. Symptoms usually start in babies, who may have difficulty breathing, but diagnosis can happen later because the condition is rare and not widely known. PCD is not contagious and cannot be caused by anything in your environment.
For more information on PCD and the treatments used for the condition, see the European Lung Foundation’s (ELF) PCD web page in the information hub.
The recommendations
Diagnosing PCD usually requires a combination of tests. There is no single test that can identify PCD and confirm the diagnosis in everyone affected so healthcare professionals should use several tests together and look at them alongside a person’s symptoms.
The main methods of testing for PCD include:
Genetic testing
Genetic testing involves taking a blood sample to look at your DNA – the instruction manual inside every cell of your body. It tests for changes (called variants or mutations) in genes known to cause PCD. So far, scientists have identified over 55 genes that can cause PCD when they don’t work properly. These genes contain the instructions for building the tiny hair-like structures (cilia) that line your airways.
While a positive result can confirm PCD, an uncertain or negative result does not rule out PCD. This is because scientists have not yet discovered all the genes and all the variants linked with PCD. Other tests can be used to help healthcare professionals learn more about what is causing a person’s symptoms.
Electron Microscopy (TEM)
For this test, a small brush is used to collect cells from inside your nose (similar to a nose swab). This is sent to a laboratory for scientists to look at the structure of the cilia. These are examined by a powerful microscope in a process called transmission electron microscopy (TEM), which can spot any problems with the cilia. Any clear issues that are found can confirm a diagnosis of PCD. In a similar way to genetic testing, if the results are normal or uncertain, this does not rule out PCD and further tests are needed to understand symptoms.
This guideline asked about which further tests should also be considered to strengthen the diagnosis of PCD.
Nasal Nitric Oxide (nNO) Test
This test measures levels of nitric oxide (NO) in the nose. These are typically low for people with PCD. Find out more about this test in the BEAT-PCD and ELF patient information leaflet on Nasal NO testing.
During the test, a small plastic, rubber or foam nasal olive (bung) connected to an analyser, is placed at the entrance of one of the nostrils and collects air for a few seconds. Measurement of nNO is simple and painless.
While the air is collected from the nose. There are different ways to do the test:
- Breathe out slowly and steadily against a mouthpiece or “party blower”,
- Or hold your breath
- Or breathe normally.
✅ Strong recommendation in favour of: using the nNO test while blowing or holding your breath, alongside genetic testing and/or TEM to help diagnose PCD.
This is best for people 5 years and older who can follow the instructions.
🤔 Conditional recommendation in favour of: using nNO during normal breathing, alongside genetic testing and/or TEM testing to help diagnose PCD.
Measuring nNO through normal breathing can be less accurate but is more suitable for young children or babies.
A normal result with either test does not rule out PCD. nNO testing should never be used alone to diagnose or exclude PCD.
High-Speed Video Microscopy (HSVM)
A small sample of cilia is taken from the nose using a brush. This test involves looking at the cilia under a microscope using a powerful high-speed camera that can watch cilia move to check for any problems.
✅ Strong recommendation in favour of: using HSVM alongside genetic testing and/or TEM testing to help diagnose PCD.
A normal result does not rule out PCD. These tests should only be done at specialist centres. The sample can be allowed to grow in the laboratory for a few weeks before it is analysed as this makes it more likely to spot any issues.
Immunofluorescence (IF):
This involves taking a sample from the nose and testing it in a laboratory using special dyes. Scientists ‘paint’ the cilia with glowing dye so they can see if any pieces are missing.
✅ Strong recommendation in favour of: immunofluorescence (IF) alongside genetic testing and/or TEM testing to help diagnose PCD.
It should be carried out in a specialist centre and it can be particularly useful when genetic testing finds uncertain results. A normal result does not rule out PCD.
Summary of recommendations
As patients with PCD experience the condition differently, multiple tests are usually needed to diagnose PCD. It is important to remember that:
- All three further tests (nNO, HSVM and IF) are all valuable and can be part of the diagnosis journey
- All tests have their own limitations and this is why multiple tests are often needed
- There is no evidence that one test should be done before or after another
- Not all tests are needed for everyone
- Tests should meet minimum standards and be carried out at specialist centres.
What does the diagnosis journey typically look like?
The guidelines recommend a step-by-step approach to getting a PCD diagnosis for healthcare professionals to follow:
Step 1: Symptom monitoring
Before any testing takes place, healthcare professionals should look at a person’s symptom history. There are common symptoms that should make doctors consider PCD. These include:
- Newborn period: Breathing difficulties in a full-term baby right after birth
- Early childhood: A wet cough that starts early and never goes away, frequent chest infections, year-round runny/stuffy nose, frequent ear infections, hearing loss
- Later childhood/adulthood: Bronchiectasis (damaged airways), chronic sinus problems, fertility issues
- Organ arrangement: Reversal of the heart and/or other organs (situs inversus)
Step 2: Main tests
Genetic testing and TEM testing can be used to look for problems with genes linked to PCD and abnormalities with cilia.
Step 3: Further testing
If the main tests are not available or they do not confirm PCD, further tests can now be used:
- nNO testing
- HSVM
- IF
Step 4: Confirming PCD
PCD can be confirmed if the genetic testing and TEM test find clear evidence of PCD.
If the main tests are uncertain, PCD is thought to be highly likely if one of the further tests is positive and the results match what a healthcare professionals suspects based on the symptoms and other test results.
PCD is thought to be unlikely if there is more than one negative test and a healthcare professional thinks that the symptoms could be something else.
It is important to remember that:
- No single test can exclude PCD in someone with strong symptoms
- Multiple negative tests make PCD less likely, but diagnosis may still need to be revisited
- Test quality is critical and tests should meet minimum standards
- Healthcare professionals can do the tests again over time as tests improve and new genes are discovered
Further reading
This guideline was produced by the European Respiratory Society and the American Thoracic Society. You can find out more about these organisations and access the full professional guideline using the links below:
- Full clinical guideline – published in the European Respiratory Journal in December 2025: ‘European Respiratory Society and American Thoracic Society guidelines for the diagnosis of primary ciliary dyskinesia | European Respiratory Society’
- Further resources for patients and carers: Primary Ciliary Dyskinesia (PCD) – European Lung Foundation
About ERS
ERS is an international organisation that brings together physicians, healthcare professionals, scientists, and other experts working in respiratory medicine. It is one of the leading medical organisations in the respiratory field, with a growing membership representing over 140 countries. The ERS mission is to promote lung health to alleviate suffering from disease and drive standards for respiratory medicine globally. Science, education, and advocacy are at the core of everything it does. ERS is involved in promoting scientific research and providing access to high-quality educational resources. It also plays a key role in advocacy – raising awareness of lung disease amongst the public and politicians. www.ersnet.org.
About ELF
ELF was founded by ERS to bring together patients and the public with professionals. ELF produces public versions of ERS guidelines to summarise the recommendations made to healthcare professionals in Europe, in a simple format for all to understand. These documents do not contain detailed information on each condition and should be used in conjunction with other patient information and discussions with your doctor. More information on lung conditions can be found on the ELF website: www.europeanlung.org.
