Objectives Autoantibodies to extractable nuclear antigens (ENA) are frequently ordered during the workup of suspected autoimmune connective tissue diseases. There are no current guidelines for repeat test ordering. The objective of this study was to assess the utility of repeat ENA testing after an initial negative result. Methods A retrospective study was conducted in a single, multicentre tertiary health network in Melbourne, Australia. Results of all ENA tests were extracted from the hospital laboratory information system. For patients who had a change in ENA result from negative to positive, clinical information was obtained from the hospital records regarding new diagnosis of an antinuclear antibody (ANA)-associated rheumatic disease (AARD). Results A total of 23 438 ENA tests were performed in 19 603 patients from 29th July 2013 to 28th September 2020. 20 918 (89.2%) were negative with 215 (0.9%) being equivocal. Of the 2,305 positive tests, the most common ENA auto-antibody specificity detected was anti-Ro52 (1,185, 51.4%). 2,636 of 19 603 patients (13.4%) had more than one ENA test performed during the study period. Of these, most (2,523, 95.7%) had stable ENA results with no change compared with the first test. Only 53 patients (2.2%) had an ENA result that changed from negative to positive. Excluding patients with pre-existing rheumatic conditions and those under 18, there were five new AARD found in the remaining 34 patients. Conclusion Repeat ENA test results rarely change or result in a new diagnosis of an AARD, with repeated testing only warranted if there is a change in clinical manifestations.

中文翻译：

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重复可提取核抗原抗体检测的效用——回顾性审计

目的 在疑似自身免疫性结缔组织病的检查过程中，经常需要针对可提取核抗原 (ENA) 的自身抗体。目前没有重复测试订购的指南。本研究的目的是评估在初始阴性结果后重复进行 ENA 检测的效用。方法 一项回顾性研究在澳大利亚墨尔本的单一、多中心三级卫生网络中进行。所有 ENA 测试的结果均从医院实验室信息系统中提取。对于 ENA 结果从阴性变为阳性的患者，从医院记录中获得有关抗核抗体 (ANA) 相关风湿病 (AARD) 新诊断的临床信息。结果 2013 年 7 月 29 日至 2020 年 9 月 28 日，共对 19 603 名患者进行了 23 438 次 ENA 检测。其中 20 918 例（89.2%）为阴性，215 例（0.9%）为不确定。在 2,305 个阳性测试中，检测到的最常见的 ENA 自身抗体特异性是抗 Ro52 (1,185, 51.4%)。19603 名患者中有 2636 名 (13.4%) 在研究期间进行了不止一次 ENA 测试。其中，大多数 (2,523, 95.7%) 的 ENA 结果稳定，与第一次测试相比没有变化。只有 53 名患者 (2.2%) 的 ENA 结果从阴性变为阳性。排除原有风湿病患者和 18 岁以下患者，在其余 34 名患者中发现了 5 名新的 AARD。结论 重复 ENA 测试结果很少改变或导致 AARD 的新诊断，