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Interpretation of the “positive” methacholine challenge
Author(s) -
Hewitt David J.
Publication year - 2008
Publication title -
american journal of industrial medicine
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.7
H-Index - 104
eISSN - 1097-0274
pISSN - 0271-3586
DOI - 10.1002/ajim.20631
Subject(s) - methacholine , medicine , asthma , bronchial hyperresponsiveness , inhalation , occupational asthma , population , test (biology) , respiratory disease , anesthesia , environmental health , lung , paleontology , biology
Abstract Background A methacholine challenge may be used in confirming the diagnosis of asthma, occupational asthma, or reactive airways dysfunction syndrome (RADS) through identification of bronchial hyperreactivity (BHR). While sensitivity of the test in diagnosing clinically significant asthma is excellent, specificity of the test is poor. Since there are many conditions which have been associated with BHR, a positive test must be interpreted cautiously. Methods This paper reviews potential causes of a positive methacholine challenge other than asthma or RADS which have been reported in the medical literature. Results Factors which may be associated with a positive methacholine test include test methodology, normal variation of BHR in the general population, and numerous medical conditions. Conclusions In cases of inhalation exposure evaluations, alternative explanations must be considered when determining whether a causal association exists between the exposure and a positive methacholine test result. Am. J. Ind. Med. 51:769–781, 2008. Published 2008 Wiley‐Liss, Inc.