ABSTRACT
Tests of respiratory function are commonly used in the diagnosis, assessment and monitoring of respiratory symptoms and disease. Their role in specic diagnosis usually depends on pattern recognition, with the results supporting or excluding a particular condition or group of conditions. One exception to this generalisation is asthma, for which demonstration of the characteristic variability of airway function may be diagnostic in itself. Breathing tests are also used to detect impaired function, to quantify its severity and to aid location of the likely anatomical site(s) of disease (e.g. airway, lung parenchyma, pulmonary vasculature, etc.). Sequential spirometric measurements are frequently employed in order to monitor the progress of disease and the response
to treatment, and in many conditions they give useful information on the prognosis.
