Functional aspects of asthma

Asthma is characterized by reversible abnormalities of maximum airflow rate, lung volumes, and gas exchange. Many different pulmonary function tests can be used to help establish the diagnosis and severity of asthma. Certain methodologic considerations and factors which modify test results are discussed in this article. Reversibility of airways disease can be established by pulmonary function tests before and after bronchodilator treatment. Bronchoprovocation tests are becoming increasingly important both in diagnosis of asthma and as a tool in clinical investigation.