In patients with a less classical history and non-confirmatory spirometry measurements, it may be necessary to resort to more sophisticated diagnostic tests, such as bronchial provocation tests (for example with methacholine, mannitol, histamine, exercise or cold air). These are really helpful in those individuals who have normal spirometry, and no evidence of variable Peak Flow.

These challenges are known to induce varying degrees of bronchoconstriction in individuals with sensitive airways, i.e. asthmatics. If a patient demonstrates bronchoconstriction following administration of, for example, a low dose of methacholine, their airways are determined to be ‘hyper-reactive’ to that compound. This can be used as objective evidence for making an asthma diagnosis.