Spirometry with Bronchodilator Response Testing

Introduction to Asthma Diagnosis

The European Respiratory Society recommends that asthma should not be diagnosed based on symptoms alone, even when classic features like recurrent wheeze and atopy are present, as this is a strong recommendation 1
Asthma diagnosis requires at least two abnormal objective tests, not just clinical suspicion, especially in children with high-risk features for persistent asthma, such as eczema plus wheezing 2
Recurrent wheeze is the most important symptom of asthma, and documented wheezing makes asthma a strong diagnostic consideration, according to the European Respiratory Journal 1

Spirometry is recommended as the first-line objective test for children aged 5-16 years under investigation for asthma, and most children in this age range can successfully perform acceptable spirometry, as recommended by the European Respiratory Society 1
Bronchodilator reversibility testing showing ≥12% improvement in lung function after bronchodilator is a key diagnostic test for asthma, according to the European Respiratory Journal 1
The European Respiratory Society suggests that testing is most useful when the child is symptomatic or when wheezing is present, as lung function tests are frequently normal during stable disease 1

If spirometry and bronchodilator reversibility testing are performed, fractional exhaled nitric oxide testing should be considered as a second objective test, as elevated levels suggest airway inflammation, as recommended by the European Respiratory Society 1
Asthma should only be diagnosed when two or more recommended diagnostic tests are abnormal, according to the European Respiratory Society 1
In patients suspected of having cough-variant asthma but with nondiagnostic physical examination and lung function tests, methacholine inhalation challenge testing should be performed to confirm airway hyperresponsiveness, as suggested by the American Thoracic Society 4

The European Respiratory Society recommends that cough should not always be assumed to represent asthma—children with chronic cough as the only symptom are unlikely to have asthma and should be investigated according to chronic cough guidelines 1
However, children with both cough and wheezing with recurrent episodes are more likely to have asthma, according to the European Respiratory Journal 1
The European Respiratory Society suggests that empiric treatment with inhaled corticosteroids or bronchodilators should not be initiated without objective confirmation, as symptom improvement after treatment alone should not be used to diagnose asthma 1