How is asthma diagnosed?

Asthma is diagnosed on the basis of medical history, symptoms, and physical examination. The doctor may also recommend breathing tests such as Peak Flow Meter test or the Spirometry test, to know the lung power and capacity.. Children below 6 years of age may not be able perform these tests. One cannot diagnose asthma with a chest X-ray, though sometimes it is done to rule out any other cause for breathing problems such as foreign bodies in the lungs or chest infections.