General safety requirements, contraindications and precautions should be strictly applied in order to minimise the risk of severe adverse events |
The duration or concentration of exposure to occupational agents should only be gradually increased under close monitoring of functional parameters |
A control challenge test with a 6–8 h period of spirometric monitoring on a separate day is required for the interpretation of the SIC results |
Changes in FEV1 should be the primary physiological outcome measure, but other functional indices (i.e. airway resistance/conductance) may be useful in subjects who are not able to complete reproducible expiratory manoeuvres |
NSBHR should be measured at least before the SIC and at the end of a negative SIC procedure. A significant increase in post-challenge NSBHR provides further evidence for a positive response when changes in FEV1 are indeterminate and indicates that additional challenges are necessary before excluding a diagnosis of occupational asthma |
Sputum eosinophils and FeNO may help interpret equivocal tests and indicate the need for longer SIC exposures to reduce the risk of false-negative results |
FEV1: forced expiratory volume in 1 s; NSBHR: nonspecific bronchial hyperresponsiveness; FeNO: exhaled nitric oxide fraction.