Hewitt David J
Center for Toxicology and Environmental Health, LLC, North Little Rock, Arkansas.
Am J Ind Med. 2008 Oct;51(10):769-81. doi: 10.1002/ajim.20631.
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.
This paper reviews potential causes of a positive methacholine challenge other than asthma or RADS which have been reported in the medical literature.
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.
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.
通过识别支气管高反应性（BHR），乙酰甲胆碱激发试验可用于确诊哮喘、职业性哮喘或反应性气道功能障碍综合征（RADS）。虽然该试验在诊断具有临床意义的哮喘方面敏感性极佳，但其特异性较差。由于有许多情况与BHR相关，因此对阳性试验结果的解读必须谨慎。
本文综述了医学文献中报道的除哮喘或RADS之外，导致乙酰甲胆碱激发试验呈阳性的潜在原因。
可能与乙酰甲胆碱试验阳性相关的因素包括试验方法、一般人群中BHR的正常变异以及众多医学状况。
在吸入暴露评估中，在确定暴露与乙酰甲胆碱试验阳性结果之间是否存在因果关系时，必须考虑其他解释。
