generate questions: Spirometry is recommended to aid in diagnosis and management. It is the single best test for asthma. If the FEV1 measured by this technique improves more than 12% following administration of a bronchodilator such as salbutamol, this is supportive of the diagnosis. It however may be normal in those with a history of mild asthma, not currently acting up. As caffeine is a bronchodilator in people with asthma, the use of caffeine before a lung function test may interfere with the results. Single-breath diffusing capacity can help differentiate asthma from COPD. It is reasonable to perform spirometry every one or two years to follow how well a person's asthma is controlled.
What is recommended to help in the diagnosis of asthma? {sep_token} Why is spirometry so commonly used to diagnose asthma? {sep_token} What helps support the evidence of asthma? {sep_token} What substance can skew the results of an asthma test? {sep_token} What test can tell the difference between asthma and COPD? {sep_token}