Chock C, Irwig L, Berry G, Glasziou P
Department of Public Health and Community Medicine, University of Sydney, NSW, Australia.
J Clin Epidemiol. 1997 Nov;50(11):1211-7. doi: 10.1016/s0895-4356(97)00122-4.
Two dichotomous screening tests are often compared by performing both tests in a sampled population, and submitting positive results on either test to verification by the reference standard. Unbiased estimates of the true positive and false positive rates of each test cannot be estimated directly. However, unbiased estimates of the relative true positive and relative false positive rates may be obtained. When one test has a higher true positive rate at the expense of a higher false positive rate, the trade-off is represented by the ratio of extra false positives detected to extra true positives detected. A 95% confidence interval for this ratio is derived. This ratio is prevalence dependent and only applies to the sampled population. For target populations of different prevalence, estimates of the ratio may be obtained if one of the following applies: (i) the test characteristics of one test are known; (ii) the relative prevalence is known; and (iii) certain assumptions are made.
两种二分筛查试验通常通过在抽样人群中同时进行这两种试验，并将任一试验的阳性结果提交给参考标准进行验证来进行比较。无法直接估计每种试验的真阳性率和假阳性率的无偏估计值。然而，可以获得相对真阳性率和相对假阳性率的无偏估计值。当一种试验以较高的假阳性率为代价获得较高的真阳性率时，这种权衡由检测到的额外假阳性与检测到的额外真阳性的比率来表示。得出该比率的95%置信区间。该比率取决于患病率，并且仅适用于抽样人群。对于不同患病率的目标人群，如果满足以下条件之一，则可以获得该比率的估计值：（i）一种试验的检测特征已知；（ii）相对患病率已知；以及（iii）做出某些假设。
