Department of Rheumatology, Allergy and Immunology, Tan Tock Seng Hospital, Singapore.
Department of General Medicine, Khoo Teck Puat Hospital, Singapore.
Singapore Med J. 2022 Mar;63(3):147-151. doi: 10.11622/smedj.2020117. Epub 2020 Aug 17.
The antinuclear antibody (ANA) test is a screening test for systemic autoimmune rheumatic disease (SARD). We hypothesised that the presence of anti-DFS70 in ANA-positive samples was associated with a false-positive ANA test and negatively associated with SARD.
A retrospective analysis of patient samples received for ANA testing from 1 January 2016 to 30 June 2016 was performed. Patient samples underwent ANA testing via indirect immunofluorescence method and anti-DFS70 testing using enzyme-linked immunosorbent assay.
Among a total of 645 ANA-positive samples, the majority (41.7%) were positive at a titre of 1:80. The commonest nuclear staining pattern (65.5%) was speckled. Only 9.5% of ANA-positive patients were diagnosed with SARD. Anti-DFS70 was found to be present in 10.0% of ANA-positive patients. The majority (51/59, 86.4%) of patients did not have SARD. Seven patients had positive ANA titre > 1:640, the presence of anti-double stranded DNA and/or anti-Ro60. The presence of anti-DFS70 in ANA-positive patients was not associated with the absence of SARD (Fisher's exact test, p = 0.245).
The presence of anti-DFS70 was associated with a false-positive ANA test in 8.6% of our patients. Anti-DFS70 was not associated with the absence of SARD.
抗核抗体（ANA）检测是系统性自身免疫性风湿病（SARD）的筛选检测。我们假设在 ANA 阳性样本中存在抗 DFS70 与假阳性 ANA 检测相关，并且与 SARD 呈负相关。
对 2016 年 1 月 1 日至 2016 年 6 月 30 日期间接受 ANA 检测的患者样本进行了回顾性分析。患者样本通过间接免疫荧光法进行 ANA 检测，通过酶联免疫吸附试验进行抗 DFS70 检测。
在总共 645 例 ANA 阳性样本中，大多数（41.7%）的滴度为 1:80 阳性。最常见的核染色模式（65.5%）为斑点型。仅有 9.5%的 ANA 阳性患者被诊断为 SARD。在 10.0%的 ANA 阳性患者中发现存在抗 DFS70。大多数（51/59，86.4%）患者未患有 SARD。7 例患者的 ANA 滴度>1:640，存在抗双链 DNA 和/或抗 Ro60。ANA 阳性患者中存在抗 DFS70 与 SARD 缺失无关（Fisher 确切检验，p=0.245）。
在我们的患者中，8.6%的抗 DFS70 与假阳性 ANA 检测相关。抗 DFS70 与 SARD 缺失无关。
