Birkett N J
Department of Clinical Epidemiology and Biostatistics, McMaster University, Hamilton, Ontario, Canada.
J Clin Epidemiol. 1988;41(5):491-4. doi: 10.1016/0895-4356(88)90051-0.
The evaluation of diagnostic tests attempts to obtain one or more statistical parameters which can indicate the intrinsic diagnostic utility of a test. Sensitivity, specificity and predictive value are not appropriate for this use. The likelihood ratio has been proposed as a useful measure when using a test to diagnose one of two disease states (e.g. disease present or absent). In this paper, we generalize the likelihood ratio concept to a situation in which the goal is to diagnose one of several non-overlapping disease states. A formula is derived to determine the post-test probability of a specific disease state. The post-test odds are shown to be related to the pre-test odds of a disease and to the usual likelihood ratios derived from considering the diagnosis between the target diagnosis and each alternate in turn. Hence, likelihood ratios derived from comparing pairs of diseases can be used to determine test utility in a multiple disease diagnostic situation.
诊断试验的评估旨在获得一个或多个能够表明试验内在诊断效用的统计参数。灵敏度、特异度和预测值并不适用于此用途。当使用一项试验来诊断两种疾病状态之一（例如疾病存在或不存在）时，似然比已被提议作为一种有用的度量。在本文中，我们将似然比的概念推广到目标是诊断几种不重叠疾病状态之一的情况。推导了一个公式来确定特定疾病状态的试验后概率。试验后比值被证明与疾病的试验前比值以及通过依次考虑目标诊断与每个替代诊断之间的诊断得出的通常似然比相关。因此，从成对疾病比较中得出的似然比可用于确定多种疾病诊断情况下的试验效用。
