Department of Pathology, Rhode Island Hospital, Providence, Rhode Island; Department of Medicine, Rhode Island Hospital, Providence, Rhode Island, USA.
J Mol Diagn. 2011 Jul;13(4):395-400. doi: 10.1016/j.jmoldx.2011.03.004. Epub 2011 Apr 29.
Performance characteristics of five assays for detection of Clostridium difficile toxin were compared using fresh stool samples from patients with C. difficile infection (CDI). Assays were performed simultaneously and according to the manufacturers' instructions. Patients were included in the study if they exhibited clinical symptoms consistent with CDI. Nonmolecular assays included glutamate dehydrogenase antigen tests, with positive findings followed by the Premier Toxin A and B Enzyme Immunoassay (GDH/EIA), and the C. Diff Quik Chek Complete test. Molecular assays (PCR) included the BD GeneOhm Cdiff Assay, the Xpert C. difficile test, and the ProGastro Cd assay. Specimens were considered true positive if results were positive in two or more assays. For each method, the Youden index was calculated and cost-effectiveness was analyzed. Of 81 patients evaluated, 26 (32.1%) were positive for CDI. Sensitivity of the BD GeneOhm Cdiff assay, the Xpert C. difficile test, the ProGastro Cd assay, C. Diff Quik Chek Complete test, and two-step GDH/EIA was 96.2%, 96.2%, 88.5%, 61.5%, and 42.3%, respectively. Specificity of the Xpert C. difficile test was 96.4%, and for the other four assays was 100%. Compared with nonmolecular methods, molecular methods detected 34.7% more positive specimens. Assessment of performance characteristics and cost-effectiveness demonstrated that the BD GeneOhm Cdiff assay yielded the best results. While costly, the Xpert C. difficile test required limited processing and yielded rapid results. Because of discordant results, specimen processing, and extraction equipment requirements, the ProGastro Cd assay was the least favored molecular assay. The GDH/EIA method lacked sufficient sensitivity to be recommended.
五种检测艰难梭菌毒素的检测方法的性能特征使用来自艰难梭菌感染（CDI）患者的新鲜粪便样本进行了比较。根据制造商的说明同时进行了检测。如果患者表现出与 CDI 一致的临床症状，则将其纳入研究。非分子检测包括谷氨酸脱氢酶抗原检测，阳性结果后进行 Premier Toxin A 和 B 酶免疫分析（GDH/EIA）和 C. Diff Quik Chek 完整检测。分子检测（PCR）包括 BD GeneOhm Cdiff 检测、Xpert C. difficile 检测和 ProGastro Cd 检测。如果两种或两种以上检测结果为阳性，则认为标本为真阳性。对于每种方法，计算了 Youden 指数并分析了成本效益。在评估的 81 名患者中，有 26 名（32.1%）对 CDI 呈阳性。BD GeneOhm Cdiff 检测、Xpert C. difficile 检测、ProGastro Cd 检测、C. Diff Quik Chek 完整检测和两步 GDH/EIA 的敏感性分别为 96.2%、96.2%、88.5%、61.5%和 42.3%。Xpert C. difficile 检测的特异性为 96.4%，其他四种检测方法的特异性为 100%。与非分子方法相比，分子方法检测到 34.7%更多的阳性标本。性能特征和成本效益评估表明，BD GeneOhm Cdiff 检测产生了最佳结果。虽然成本高昂，但 Xpert C. difficile 检测需要的处理过程有限，并且能够快速得出结果。由于存在不一致的结果、标本处理和提取设备要求，ProGastro Cd 检测是最不受欢迎的分子检测方法。GDH/EIA 方法的灵敏度不足，不建议推荐。
