Universiti Kebangsaan Malaysia, Faculty of Medicine, Kuala Lumpur, Malaysia.
Universiti Kebangsaan Malaysia, Faculty of Medicine, Department of Medical Microbiology and Immunology, Kuala Lumpur, Malaysia.
Malays J Pathol. 2024 Apr;46(1):63-69.
Anti-nuclear antibody (ANA) testing is among the most common immunological test requested in the diagnostic immunology laboratory. The main purpose of this test is to screen for the underlying systemic autoimmune rheumatic diseases (SARDs). The gold standard laboratory method for ANA detection is by the indirect immunofluorescence (IIF) assay. In most laboratories, positive ANA-IIF is reported in terms of titration and pattern.
This study was conducted with the aim of determining the correlation between ANA-IIF titration and pattern for the diagnosis of SARDs.
A retrospective study was conducted whereby the positive ANA-IIF samples from 1st July 2018 until 31st December 2019 and 1st January 2021 until 31st March 2021 were included in this study. The duplicate samples were excluded. ANA-IIF titration and pattern were recorded for all patients. The demographic, clinical, and final diagnosis data were retrieved from each patient's clinical note.
A total of 179 patients were included for analysis. The majority of the patients were female (79.9%) and from Malay ethnicity (66.5%). Sixty-five patients (36.3%) had ANA-IIF positive at 1:80 titration followed by 45 patients (25.1%) positive at titration of equal or more than 1:160. Speckled was the predominant pattern visualised in 90 patients (50.3%) followed by homogeneous in 76 patients (42.5%). Forty-five patients (25.1%) were finally diagnosed with SARDs with 41 of them diagnosed as SLE. ANA titration was significantly associated with the final diagnosis of SARDs at all titres (p<0.001) but the best cut-off was noted at a titre of equal or more than 1:320 with the sensitivity and specificity of 86.7% and 77.6% respectively. The homogeneous pattern was also significantly associated with SARDs (p=0.04). The final diagnosis of SARDs were significantly higher in female (p=0.03) and their age was significantly younger (p<0.001).
ANA-IIF titration of equal or more than 1:320 can be used as the best titration for differentiating between SARDs and non-SARDs in a positive ANA sample. Patients with homogeneous pattern were more likely to be diagnosed with SARDs than other ANA-IIF patterns.
抗核抗体（ANA）检测是诊断免疫学实验室中最常见的免疫学检测之一。该检测的主要目的是筛查潜在的系统性自身免疫性风湿病（SARDs）。ANA 检测的金标准实验室方法是间接免疫荧光（IIF）检测。在大多数实验室中，ANA-IIF 的阳性结果以滴度和模式报告。
本研究旨在确定 ANA-IIF 滴度和模式与 SARDs 诊断之间的相关性。
本研究采用回顾性研究方法，纳入了 2018 年 7 月 1 日至 2019 年 12 月 31 日和 2021 年 1 月 1 日至 2021 年 3 月 31 日期间的阳性 ANA-IIF 样本。排除了重复样本。记录了所有患者的 ANA-IIF 滴度和模式。从每位患者的临床记录中检索了人口统计学、临床和最终诊断数据。
共有 179 名患者纳入分析。大多数患者为女性（79.9%），马来族裔（66.5%）。65 名患者（36.3%）ANA-IIF 滴度为 1:80，45 名患者（25.1%）滴度为 1:160 或更高。90 名患者（50.3%）观察到斑点状模式，76 名患者（42.5%）观察到均一性模式。45 名患者（25.1%）最终被诊断为 SARDs，其中 41 名被诊断为系统性红斑狼疮。ANA 滴度与所有滴度的 SARDs 最终诊断均显著相关（p<0.001），但最佳截断值在 1:320 或更高时，其灵敏度和特异性分别为 86.7%和 77.6%。均一性模式也与 SARDs 显著相关（p=0.04）。女性（p=0.03）和年轻患者（p<0.001）的 SARDs 最终诊断率更高。
ANA-IIF 滴度为 1:320 或更高可用于区分阳性 ANA 样本中的 SARDs 和非 SARDs。均一性模式患者更有可能被诊断为 SARDs，而非其他 ANA-IIF 模式。
