How to interpret spirometry in a child with suspected asthma

Asthma is one of the most common chronic disorders of childhood. The typical symptoms are a result of reversible airway obstruction. There is no ‘gold-standard’ test to diagnose asthma, but the most commonly used investigation to help with a diagnosis is spirometry. This article outlines some of the technical aspects of spirometry together with how the forced expiration manoeuver and bronchodilator responsiveness testing can be performed and interpreted in a child with suspected asthma.