Speaker's Highlight

• Don Sin University of British Columbia, St. Paul Hospital (Canada)
  Kenneth R. Chapman Toronto General Hospital Research Institute (Canada)
• Parameswaran Nair McMaster University (Canada)
  Carolyn Calfee UCSF (U.S.A.)
• Gregory P. Downey University of Colorado School of Medicine (U.S.A.)
  David A. Schwartz University of Colorado School of Medicine (U.S.A.)
• Neil Schluger Tuberculosis Control Branch, California Department of Public Health (U.S.A.)
  Nick Kim Critical Care & Sleep Medicine, University of California San Diego (U.S.A.)
• Nicola Hananiah Baylor College of Medicine (U.S.A.)
  Jae-Joon Yim Seoul National University College of Medicine (Republic of Korea)
• Koichiro Asano Tokai University School of Medicine (Japan)
  Diahn-Warng Perng Taipei Veterans General Hospital (Taiwan)
• Konstantinos Kostikas University of Ioannina (Greece)
  Karin Klooster University Medical Center Groningen (Kingdom of the Netherlands)

• Using Nasal Nitric Oxide to Screen for Primary Ciliary Dyskinesia

  Primary ciliary dyskinesia (PCD) is an inherited disorder in which microscopic cilia do not move mucus effectively. The result can be a lifelong pattern of wet cough, recurrent chest infections, chronic nasal congestion, sinus disease, hearing problems and, in some people, infertility. Because these symptoms overlap with asthma, cystic fibrosis, immune disorders and common childhood infections, diagnosis is often delayed. Learn more about 動的ストレッチングと静的ストレッチングの比較.

  Nasal nitric oxide (nNO) offers a quick, non-invasive way to identify people who may need formal PCD testing. It is particularly useful in respiratory clinics when it is interpreted alongside the clinical history, examination and other investigations. A low reading can raise suspicion, but it cannot confirm PCD on its own.

  What PCD Is And Why Screening Matters

  Healthy airway lining produces nitric oxide in the nasal passages, especially in the paranasal sinuses. People with PCD commonly have markedly reduced nNO levels, although the biological reasons are complex and can vary between individuals. This makes nNO a useful screening biomarker rather than a stand-alone diagnostic test.

  Suspicion should increase when a child has a daily wet cough beginning in early childhood, persistent nasal discharge, recurrent otitis media, unexplained bronchiectasis or respiratory symptoms in the newborn period. Situs inversus or another laterality defect is an important clue, but its absence does not exclude PCD. Adults may present with longstanding sinus disease, bronchiectasis or reduced fertility instead.

  In Australia, referral patterns may differ between metropolitan centres such as Sydney, Melbourne, Brisbane, Perth and Adelaide and regional areas. A family might first see a general practitioner, paediatrician, respiratory physician or ear, nose and throat specialist before reaching a centre with specialist PCD expertise.

  How Nasal Nitric Oxide Testing Works

  Testing generally uses a chemiluminescence analyser or another validated nitric oxide device connected to a nasal probe. The patient breathes through the mouth while one nostril is gently sampled. Depending on age and cooperation, the technique may involve a breath hold, exhalation against resistance or tidal breathing. The method must be recorded because results from different manoeuvres are not interchangeable.

  The child should be calm and able to follow instructions. A blocked nose, recent viral infection, active sinus inflammation, nosebleed or poor seal around the probe can produce an unreliable or falsely low result. Young children may struggle with the required breathing manoeuvre, so an apparently low value may need careful review or repeat testing when the child is well.

  Pre-test preparation should be simple and reassuring. Families may ask about movement or breathing exercises before the appointment; a concise stretching comparison can help explain why gentle activity and static holds are different, although neither should replace the quiet, standardised conditions required for nNO measurement.

  Interpreting Results In Australian Practice

  A very low nNO in a cooperative patient with a compatible history is a strong reason to continue PCD assessment. Laboratories should use age-appropriate reference values, validated equipment and locally accepted quality-control procedures. Clinicians should avoid treating a single number as a universal diagnostic threshold because readings vary with age, technique, device and current nasal health.

  A normal or borderline result does not always end the investigation. Some people with PCD can have higher nNO values, and technical problems may obscure a genuine abnormality. Conversely, low readings may occur with acute upper-airway illness or significant nasal obstruction. Testing should therefore be repeated after recovery when necessary.

  Confirmatory assessment may include nasal nitric oxide on more than one occasion, high-speed video microscopy of ciliary motion, transmission or immunofluorescence studies, genetic testing and, in selected cases, electron microscopy. Chest imaging, spirometry, sputum culture and hearing assessment help define disease impact and identify alternative diagnoses.

  Australian clinicians also need to consider access and cost. Medicare coverage, public hospital pathways and private testing availability can vary by state and service. Families may need clear information about referral requirements, travel to a tertiary centre and whether a particular test is performed by a National Association of Testing Authorities-accredited laboratory.

  Building A Safe Diagnostic Pathway

  The most useful approach begins with a structured history. Ask when the cough started, whether it is wet every day, how often antibiotics have been needed, whether there was neonatal respiratory distress, and whether relatives have similar symptoms. Enquire about chronic ear disease, sinus problems, fertility concerns and any known organ laterality changes.

  nNO should be positioned as a screening step within that pathway. A low result usually warrants specialist review rather than immediate labelling. A normal result can reduce the likelihood of PCD in a suitable patient, but ongoing red flags should prompt further discussion with a respiratory physician.

  Patient information should explain the purpose of the test, possible limitations and what may happen next. This is especially important for families travelling from regional or remote communities, where repeating a test may require time away from school, work or caring responsibilities. Information about the congress and respiratory medicine services can be found through the APSR useful information resource.

  Privacy and consent also matter. Genetic testing may reveal information relevant to relatives, while clinical records and laboratory data must be handled under Australian privacy requirements, including the Privacy Act 1988 where applicable. Children should receive explanations suited to their age, and parents should understand how results will be shared between primary care, hospitals and laboratories.

  Practical Recommendations For Clinicians And Families

  Use the test most effectively by combining technical consistency with careful clinical judgement:

  • Screen patients with a persistent wet cough, early respiratory disease, chronic sinus or ear problems, bronchiectasis, or laterality abnormalities.
  • Avoid interpreting a low reading during an acute cold, severe nasal blockage or an unsuccessful breathing manoeuvre as definitive evidence of PCD.
  • Record the analyser, sampling method, patient age, manoeuvre, nasal symptoms and quality-control information with every result.
  • Repeat an abnormal or technically uncertain test when the patient is well and able to cooperate.
  • Refer patients with a compatible history and persistently low nNO to a specialist centre for confirmatory investigations.
  • Explain possible costs, Medicare or hospital pathways, travel requirements and expected waiting times before testing.
  • Keep PCD, cystic fibrosis, asthma, immunodeficiency and other causes of chronic suppurative lung disease in the differential diagnosis.

  The strength of nasal nitric oxide lies in its speed, safety and ability to prioritise patients for specialist assessment. Its value is greatest when the result is interpreted within a complete clinical picture and followed by appropriate confirmatory testing.

  The key point to remember is that a low nNO reading is a meaningful signpost, not a final diagnosis: reliable technique, repeat assessment and specialist evaluation are what turn screening into sound clinical care.

  Richard Russell Nuffield Department of Clinical Medicine, University of Oxford (United Kingdom)
• Mona Bafadhel King’s College London (United Kingdom)
  David Jackson Guy’s and St Thomas’ Hospital, King’s College London (United Kingdom)
• James Chalmers University of Dundee (United Kingdom)
  David Price University of Aberdeen (United Kingdom)