Green T A, Black C M, Johnson R E
Division of AIDS, STD, and TB Laboratory Research, National Center for Infectious Diseases, Centers for Disease Control and Prevention, Atlanta, Georgia 30333, USA.
J Clin Microbiol. 1998 Feb;36(2):375-81. doi: 10.1128/JCM.36.2.375-381.1998.
When a new diagnostic test is potentially more sensitive than the reference test used to classify persons as infected or uninfected, a substantial number of specimens from infected persons may be reference-test negative but new-test positive. Discrepant analysis involves the performance of one or more additional tests with these specimens, reclassification as infected those persons for whom the new-test-positive results are confirmed, and recalculation of the estimates of new-test sensitivity and specificity by using the revised classification. This approach has been criticized because of the bias introduced by the selective use of confirmation testing. Under conditions appropriate for evaluating a nucleic acid amplification (NAA) test for Chlamydia trachomatis infection with cell culture as the reference test, we compared the bias in estimates based on the discrepant-analysis classification of persons as infected or uninfected with that in estimates based on the culture classification. We concluded that the bias in estimates of NAA-test specificity based on discrepant analysis is small and generally less than that in estimates based on culture. However, the accuracy of discrepant-analysis-based estimates of NAA-test sensitivity depends critically on whether culture specificity is equal to or is slightly less than 100%, and it is affected by competing biases that are not fully taken into account by discrepant analysis.
当一种新的诊断测试可能比用于将个体分类为感染或未感染的参考测试更敏感时，大量来自感染个体的标本可能会出现参考测试为阴性但新测试为阳性的情况。差异分析包括对这些标本进行一项或多项额外测试，将新测试结果为阳性且得到确认的个体重新分类为感染个体，并使用修订后的分类重新计算新测试的敏感性和特异性估计值。这种方法受到了批评，因为选择性地使用确认测试会引入偏差。在适合以细胞培养作为参考测试来评估沙眼衣原体感染核酸扩增（NAA）测试的条件下，我们比较了基于差异分析将个体分类为感染或未感染时估计值中的偏差与基于培养分类时估计值中的偏差。我们得出结论，基于差异分析的NAA测试特异性估计值中的偏差较小，通常小于基于培养的估计值中的偏差。然而，基于差异分析的NAA测试敏感性估计值的准确性关键取决于培养特异性是否等于或略小于100%，并且它受到差异分析未充分考虑的相互竞争偏差的影响。
