Holle J U, Hellmich B, Backes M, Gross W L, Csernok E
Department of Rheumatology, University of Schleswig-Holstein Campus Lübeck and Rheumaklinik Bad Bramstedt, Germany.
Ann Rheum Dis. 2005 Dec;64(12):1773-9. doi: 10.1136/ard.2005.035279. Epub 2005 Apr 20.
Previous studies have shown considerable variation in diagnostic performance of enzyme linked immunosorbent assays (ELISAs) for measuring antineutrophil cytoplasmic antibodies (ANCA) specific for proteinase 3 (PR3) and myeloperoxidase (MPO).
To analyse the performance characteristics of different commercially available direct ANCA ELISA kits.
ELISA kits for detecting PR3-ANCA and MPO-ANCA from 11 manufacturers were evaluated. Serum samples were taken from patients with Wegener's granulomatosis (15), microscopic polyangiitis (15), other vasculitides (10), and controls (40).
were compared with data obtained by indirect immunofluorescence (IFT). The diagnostic performance of the tests was analysed and compared by receiver operating characteristic (ROC) curve analysis.Results: Applying the manufacturers' cut off resulted in great variation in sensitivity of the commercial PR3-ANCA kits for diagnosing Wegener's granulomatosis (ranging from 13.3% to 66.7%), and of the MPO-ANCA kits for diagnosing microscopic polyangiitis (ranging from 26.7% to 66.7%). Specificities were relatively constant (from 96.0% to 100%). IFT was superior to all ELISAs (C-ANCA for Wegener's granulomatosis: sensitivity 73.3%, specificity 98%; P-ANCA for microscopic polyangiitis: sensitivity 86.7%, specificity 98%). The sensitivities of PR3-ANCA and MPO-ANCA ELISA kits were increased by lowering the cut off values. This reduced specificity but increased overall diagnostic performance.
The low sensitivity of some commercial kits reflects the high cut off levels recommended rather than methodological problems with the assays. Comparative analyses using sera from well characterised patients may help identify optimum cut off levels of commercial ANCA ELISA tests, resulting in better comparability of results among assays from different manufacturers.
先前的研究表明，用于检测蛋白酶3（PR3）和髓过氧化物酶（MPO）特异性抗中性粒细胞胞浆抗体（ANCA）的酶联免疫吸附测定（ELISA）的诊断性能存在很大差异。
分析不同市售直接ANCA ELISA试剂盒的性能特征。
对来自11家制造商的检测PR3-ANCA和MPO-ANCA的ELISA试剂盒进行评估。血清样本取自韦格纳肉芽肿患者（15例）、显微镜下多血管炎患者（15例）、其他血管炎患者（10例）和对照者（40例）。
与间接免疫荧光法（IFT）获得的数据进行比较。通过受试者操作特征（ROC）曲线分析对检测的诊断性能进行分析和比较。结果：应用制造商推荐的临界值时，市售PR3-ANCA试剂盒诊断韦格纳肉芽肿的敏感性差异很大（范围为13.3%至66.7%），MPO-ANCA试剂盒诊断显微镜下多血管炎的敏感性差异也很大（范围为26.7%至66.7%）。特异性相对稳定（从96.0%至100%）。IFT优于所有ELISA检测（韦格纳肉芽肿的C-ANCA：敏感性73.3%，特异性98%；显微镜下多血管炎的P-ANCA：敏感性86.7%，特异性98%）。降低PR3-ANCA和MPO-ANCA ELISA试剂盒的临界值可提高其敏感性。这会降低特异性，但提高整体诊断性能。
一些市售试剂盒的低敏感性反映了推荐的临界值较高，而非检测方法本身存在问题。使用特征明确的患者血清进行比较分析，可能有助于确定市售ANCA ELISA检测的最佳临界值，从而使不同制造商的检测结果具有更好的可比性。
