Well the diagnosis of childhood asthma is done keeping in mind the child’s medical history, the symptoms developed, family history and by performing various tests. Thorough studies are to be done to notify the symptoms since many children with asthma appear and sound absolutely normal.

Spirometry testing is the most accurate and widely accepted test for diagnosing asthma. It measures the volume of air the child blows out of their lung after taking a deep breath. This test is generally taken up after the child uses inhaler.

Peak flow rate measurement or peak expiratory flow rate is done using an instrument called peak flow meter. The child is asked to inhale a very deep breath and exhale it quickly with as much pressure as possible.

Challenge testing involves a bronchial challenge in which the testing is designed to cause the airways to narrow in children with asthma. Methacholine or cold air challenge is one such test in which methacholine is given with gradual increased quantity and then spirometry testing is done. 20% decline in spirometry with any dose means the positive result. Sometimes exercise challenge is also performed.

Additional testing includes chest X-ray, sweat chloride test, barium swallow or skin testing (for allergies).