Unlike other conditions, there is no single test to establish a diagnosis of asthma. Instead a diagnosis is made by gathering information from an individual, and using that information to weigh up how likely they are to have asthma. Information can be gathered from the symptoms described, past or family history, findings from a physical examination, lung function and other clinical tests. In some cases, a diagnosis of asthma is clear from the information given and treatment can be started. However, for a large number of people, the diagnosis isn’t clear, and more information is needed before asthma can be ruled in or out.

The fact that asthma isn’t always straightforward to diagnose can lead to problems. Individuals can be wrongly diagnosed: being told they have asthma when in fact they don’t. Also known as over-diagnosis, the main consequences are unnecessary treatment, exposing patients to medicines with unhelpful long term effects and at a financially cost.

Improving the way in which asthma is diagnosed is very important. Identifying the most important aspects of information that can be gathered and using them to make a prediction score would help Doctors to weigh up the likelihood of asthma more easily and accurately.