Epidemiology Branch, National Institute of Environmental Health Sciences, National Institutes of Health, Research Triangle Park, North Carolina 27709-2233, USA.
Am J Epidemiol. 2011 Mar 1;173(5):544-52. doi: 10.1093/aje/kwq392. Epub 2011 Jan 27.
Allergic conditions and biochemical measures are both used to characterize atopy. To assess questionnaires' ability to predict biochemical measures of atopy, the authors used data on 5 allergic conditions (allergy, hay fever, eczema, rhinitis, and itchy rash) and serum-specific immunoglobulin E (IgE) levels from the 2005-2006 National Health and Nutrition Examination Survey. Atopy was defined as 1 or more positive specific IgEs (≥0.35 kU/L). Questionnaire responses were assessed for sensitivity, specificity, and positive and negative predictive values for atopy. In this population-based US sample, 44% of participants were specific IgE-positive and 53% reported at least 1 allergic condition. Discordance between atopy and allergic conditions was considerable; 37% of persons with atopy reported no allergic condition, and 48% of persons who reported an allergic condition were not atopic. Thus, no combination of self-reported allergic conditions achieved both high sensitivity and high specificity for IgE. The positive predictive value of reported allergic conditions for atopy ranged from 50% for eczema to 72% for hay fever, while the negative predictive value ranged from 57% for eczema to 65% for any condition. Given the high proportion of asymptomatic participants who were specific IgE-positive and persons who reported allergic conditions but were specific IgE-negative, it is unlikely that questionnaires will ever capture the same participants as those found to be atopic by biochemical measures.
过敏状况和生物化学指标均可用于特应性的特征描述。为了评估问卷预测特应性生物化学指标的能力，作者使用了来自 2005-2006 年全国健康和营养调查的数据，这些数据包括 5 种过敏状况（过敏、花粉热、湿疹、鼻炎和瘙痒性皮疹）和血清特异性免疫球蛋白 E（IgE）水平。特应性定义为 1 种或多种阳性特异性 IgE（≥0.35 kU/L）。评估了问卷对特应性的敏感性、特异性以及阳性和阴性预测值。在这个基于人群的美国样本中，44%的参与者为特异性 IgE 阳性，53%的参与者报告至少有一种过敏状况。特应性和过敏状况之间存在相当大的差异；37%的特应性患者没有报告过敏状况，而 48%报告过敏状况的患者并非特应性。因此，没有一种自我报告的过敏状况组合能够同时具有高敏感性和高特异性的 IgE。报告的过敏状况对特应性的阳性预测值范围为湿疹的 50%至花粉热的 72%，而阴性预测值范围为湿疹的 57%至任何状况的 65%。鉴于有相当比例的无症状参与者为特异性 IgE 阳性，而报告过敏状况但特异性 IgE 阴性的人，调查问卷不太可能与通过生物化学指标发现的特应性参与者完全相同。
