Alternative Names spirogram , pulmonary function tests
Definition Spirometry is a test of lung function. It determines how much air a person can exhale, how fast a person can exhale, and how much air a person can inhale.
The test helps diagnose lung diseases such as asthma, a condition that causes inflammation and obstruction of the airways in the lungs, bronchitis, or inflammation of the bronchial tubes in the lungs, and emphysema, a lung disease caused by abnormally large air spaces. It can also be used to monitor the treatment of lung disease. A third purpose of the test is to determine the causes of respiratory problems such as shortness of breath.
Who is a candidate for the test? This test is normally performed to diagnose or monitor lung problems. This test may also be used to evaluate the lungs before surgery.
How is the test performed? The test is performed in the doctor's office using a simple instrument called a spirometer. The person taking the test puts the instrument in his or her mouth and inhales as much air as the lungs will hold, then blow out the air as fast and for as long as possible. The spirometer records the volume that the lungs can exhale and the speed with which exhalation occurs.
What is involved in preparation for the test? Individuals should request specific instructions from their doctors on how to prepare for this test. Depending on why the test is being done, the doctor may request that some medications not be taken prior to the test.
What do the test results mean? A person's spirometer reading is evaluated by comparing it with values from a standard table. The table provides values based on a person's age, sex, and body size.
Abnormal results may indicate:
lung disease
exposure to contaminants in the air
changes in lung function due to medications
Author: David T. Moran, MD Reviewer: HealthAnswers Australia Medical Review Panel Editor: Dr David Taylor, Chief Medical Officer HealthAnswers Australia Last Updated: 1/10/2001 Contributors Potential conflict of interest information for reviewers available on request
