The use of bronchial provocation tests for identifying asthma A review of the problems for occupational assessment and a proposal for a new direction

◆ People with asthma are excluded from some occupations, including service in the Australian Defence Force, and asthma can be exacerbated by some occupations, making it desirable to identify currently active asthma and assess its severity in potential entrants. ◆ Objective testing of asthma is by bronchial provocation test (BPT). There are two types of BPT: direct and indirect. Pharmacological agents such as histamine and methacholine act directly on smooth muscle to cause contraction and airway narrowing. Physical challenges such as hyperpnoea and hyperosmolar stimuli cause smooth muscle contraction “indirectly” via the action of mediators released from inflammatory cells in response to the physical stimulus. ◆ Direct BPTs, which are commonly used in assessing ADF recruits, may not identify exercise-induced asthma, but can give false-positive results. ◆ For more accurate assessment, we propose a new testing algorithm consisting of two parts. The first identifies individuals with currently active asthma using indirect BPT. The second identifies individuals who may have an increased propensity for developing asthma using direct BPT. ◆ Standardised indirect BPTs are a practical tool for identifying active asthma for occupational entry. While the direct BPT and skin testing may help potential employees decide whether to enter occupations with a high risk of inducing asthma, it may not be ethical to use these tests to exclude them. Objective testing for currently active asthma or risk of asthma would permit ADF Health 2002; 3: 77-85 fair decision-making in the workplace. Respiratory Medicine