Normal non-specific reactivity excluded occupational asthma?

References

	Pralong JA, Lemière C, Rochat T, L'Archevêque J, Labrecque M, Cartier A, Predictive value of nonspecific bronchial responsiveness in occupational asthma, J Allergy Clin Immunol, 2016;137:412-416,http://dx.doi.org/10.1016/j.jaci.2015.06.026

Comments

This study reports a a very high sensitivity for non-specific reactivity in predicting a positive specific challenge test to an occupational agent. Most of those with negative NSBR were away from exposure at the time of the test, something generally found by others. The high sensitivity is partly explained by using a higher cut-off for normality (16mg/ml) than the usual 8mg/ml, but this is still unlikely to explain the very high sensitivity found. We need assurance that NSBR was not used to decide who should have a specific challenge (this is recommended in some guidelines). Another possible explanation is the high prevalence of the eosinophilic phenotype, something associated with NSBR. Others have found much lower sensitivities for NSBR in predicting the response to specific challenges, particular in those without sputum eosinophilia. The specificities quoted depend on the controls selected (or in this case those with negative specific challenges) as NSBR cannot separate occupational from non-occupational asthma.

2/8/2016