ROS-1免疫组织化学（IHC）是非小细胞肺癌临床治疗中筛查ROS1融合的常用方法。然而，ROS-1 SP384 IHC的解释标准尚未确定。 65例非小细胞肺癌病例接受了AmoyDx ROS1融合实时聚合酶链反应（PCR）研究和ROS-1 SP384 IHC测试，并检索到这些结果进行分析。 ROS-1 IHC 测试是根据已建立的分类器以及弥漫性同质免疫反应性的存在来解释的。通过与 ROS1 实时 PCR 结果进行比较来评估这些 ROS-1 IHC 解释方法的诊断准确性。以前的 ROS-1 IHC 分类器对阳性 ROS1 实时 PCR 结果表现出高灵敏度 (100%)，但它们显示特异性低（25%-50%），总体准确度低（58%-72%）。相比之下，弥散均质 ROS-1 免疫反应性预测阳性 ROS1 实时 PCR 结果具有更高的特异性 (94%) 和总体准确性 (95%)，但灵敏度稍低 (97%)。一些显示弥散均质 ROS-1 免疫反应性和实时 PCR 结果之间存在差异的病例涉及罕见的 ROS1::LDLR 融合和次优 IHC 染色。ROS-1 SP384 IHC 测试的 3 层报告系统结合了先前的解释标准和弥散和均质免疫反应性可以在不降低特异性的情况下更好地预测 ROS1 融合状态。© 作者 2024。由牛津大学出版社代表美国临床病理学会出版。版权所有。如需商业重复使用，请联系 reprints@oup.com 获取转载和转载的翻译权。所有其他权限都可以通过我们网站文章页面上的权限链接通过我们的 RightsLink 服务获得 - 如需更多信息，请联系journals.permissions@oup.com。

ROS-1 immunohistochemistry (IHC) is a common method for screening ROS1 fusion in the clinical management of non-small cell lung cancer. The interpretation criteria for ROS-1 SP384 IHC, however, remain unestablished.Sixty-five non-small cell lung cancer cases underwent AmoyDx ROS1 fusion real-time polymerase chain reaction (PCR) study and ROS-1 SP384 IHC tests, which were retrieved for analysis. ROS-1 IHC tests were interpreted based on the established classifiers as well as the presence of diffuse homogeneous immunoreactivity. The diagnostic accuracies of these ROS-1 IHC interpretation methods were evaluated by comparing them with the ROS1 real-time PCR results.Previous ROS-1 IHC classifiers demonstrated high sensitivity for positive ROS1 real-time PCR results (100%), but they showed low specificities (25%-50%) and overall accuracies (58%-72%). In contrast, the diffuse homogeneous ROS-1 immunoreactivity predicted positive ROS1 real-time PCR results with much higher specificity (94%) and overall accuracy (95%), albeit with a slightly lower sensitivity (97%). Some cases that showed discrepancy between diffuse homogeneous ROS-1 immunoreactivity and real-time PCR results involved rare ROS1::LDLR fusion and suboptimal IHC staining.A 3-tier reporting system for ROS-1 SP384 IHC testing combining previous interpretation criteria and diffuse and homogeneous immunoreactivity may better predict ROS1 fusion status without decreasing specificity.© The Author(s) 2024. Published by Oxford University Press on behalf of American Society for Clinical Pathology. All rights reserved. For commercial re-use, please contact reprints@oup.com for reprints and translation rights for reprints. All other permissions can be obtained through our RightsLink service via the Permissions link on the article page on our site—for further information please contact journals.permissions@oup.com.