Department of Laboratory Medicine, Yale University School of Medicine, New Haven, Connecticut, USA
Clinical Virology Laboratory, Yale New Haven Hospital, New Haven, Connecticut, USA.
J Clin Microbiol. 2020 Jan 28;58(2). doi: 10.1128/JCM.01629-19.
The Singulex Clarity C. diff toxins A/B (Clarity) assay is an automated, ultrasensitive immunoassay for the detection of toxins in stool. In this study, the performance of the Clarity assay was compared to that of a multistep algorithm using an enzyme immunoassay (EIA) for detection of glutamate dehydrogenase (GDH) and toxins A and B arbitrated by a semiquantitative cell cytotoxicity neutralization assay (CCNA). The performance of the assay was evaluated using 211 residual deidentified stool samples tested with a GDH-and-toxin EIA (C. Diff Quik Chek Complete; Techlab), with GDH-and-toxin discordant samples tested with CCNA. The stool samples were stored at -80°C before being tested with the Clarity assay. For samples discordant between Clarity and the standard-of-care algorithm, the samples were tested with PCR (Xpert ; Cepheid), and chart review was performed. The testing algorithm resulted in 34 GDH/toxin, 53 GDH/toxin, and 124 GDH/toxin samples, of which 39 were CCNA and 85 were CCNA Clarity had 96.2% negative agreement with GDH/toxin samples, 100% positive agreement with GDH/toxin samples, and 95.3% agreement with GDH/toxin/CCNA samples. The Clarity result was invalid for one sample. Clarity agreed with 61.5% of GDH/toxin/CCNA samples, 90.0% of GDH/toxin/CCNA (high-positive) samples, and 31.6% of GDH/toxin/CCNA (low-positive) samples. The Singulex Clarity C. diff toxins A/B assay demonstrated high agreement with a testing algorithm utilizing a GDH-and-toxin EIA and CCNA. This novel automated assay may offer an accurate, stand-alone solution for infection (CDI) diagnostics, and further prospective clinical studies are merited.
Singulex Clarity C. diff 毒素 A/B（Clarity）检测法是一种用于检测粪便中毒素的自动化、超敏免疫检测法。在这项研究中，Clarity 检测法的性能与使用酶免疫测定法（EIA）检测谷氨酸脱氢酶（GDH）和毒素 A、B，并用半定量细胞细胞毒性中和测定法（CCNA）仲裁的多步算法进行了比较。使用与 GDH 和毒素 EIA（C. Diff Quik Chek Complete；Techlab）检测呈 GDH 和毒素不一致的 CCNA 检测法对 211 份经鉴定的粪便残留样本进行了检测，评估了该检测法的性能。这些粪便样本在进行 Clarity 检测前储存在-80°C。对于 Clarity 与标准护理算法不一致的样本，使用 PCR（Xpert；Cepheid）进行了检测，并进行了图表审查。该检测算法导致 34 份 GDH/毒素、53 份 GDH/毒素和 124 份 GDH/毒素样本，其中 39 份为 CCNA，85 份为 CCNA Clarity 与 GDH/毒素样本的阴性一致性为 96.2%，与 GDH/毒素样本的阳性一致性为 100%，与 GDH/毒素/CCNA 样本的一致性为 95.3%。一个样本的 Clarity 结果无效。Clarity 与 61.5%的 GDH/毒素/CCNA 样本、90.0%的 GDH/毒素/CCNA（高阳性）样本和 31.6%的 GDH/毒素/CCNA（低阳性）样本一致。Singulex Clarity C. diff 毒素 A/B 检测法与使用 GDH 和毒素 EIA 以及 CCNA 的检测算法具有高度一致性。这种新型自动化检测法可能为 感染（CDI）诊断提供一种准确、独立的解决方案，值得进一步开展前瞻性临床研究。
