The second article in CMAJ's (Canadian Medical Association Journal's) www.cmaj.com series on asthma provides practical guidance for the diagnosis of adult asthma, including occupational asthma.

Because asthma is quite common and may need lifelong treatment, an accurate diagnosis is important. In Canada, it is the most common chronic respiratory disease, with approximately 2.2 million adults and 800,000 children affected. However, asthma control is uneven and suboptimal, despite improvements in diagnosis and treatment.

People with episodic breathlessness, wheezing, cough, sputum or chest tightness may have asthma and need to be assessed by a physician using patient history, physical examination and then definitive diagnostic testing. Spirometry or peak measurement flow testing objectively assesses lung function. These tests, supplemented occasionally by challenge testing, will allow the physician to diagnose or exclude the possibility of asthma and to treat the patient accordingly.

The article is based on Canadian guidelines and new guidelines from other countries, existing asthma literature and the authors' clinical experience.