B-107 Serodiagnosis of Anti-glomerular Basement Membrane Disease Using a Newly Developed Chemiluminescence Immunoassay

Abstract

Abstract Background Autoantibodies against the glomerular basement membrane (GBM) are important markers in the diagnosis and monitoring of autoimmune glomerulonephritides. Fast and reliable detection of these autoantibodies is crucial as anti-GBM disease can progress rapidly with fatal outcome. Here, we investigated the diagnostic performance of a newly developed, standardized anti-GBM chemiluminescence immunoassay (ChLIA). Methods The diagnostic performance of the EUROIMMUN Anti-GBM ChLIA (IgG), processed on the EUROIMMUN RA Analyzer 10, was assessed using sera from 67 clinically characterized anti-GBM disease patients and 221 disease controls. Results were compared with those obtained by the EUROIMMUN Anti-GBM ELISA (IgG). Inter-assay concordance, measurement range and interference were determined in a subset of samples. Results The ChLIA reached 100% sensitivity at a specificity of 98.6%, while the ELISA was less sensitive (89.6%) and more specific (100%). High qualitative concordance between both assays was evidenced by positive and negative agreement rates of 100% and 95.6%, respectively, and a kappa score of 0.901. The ChLIA showed linearity within a measurement range of 3.8–517.3 CU/mL. Coefficients of variation were calculated as 1.2%–3.3% (intra-lot) and 1.6%–4.2% (inter-lot). No interference was observed for hemolyzed, lipemic or icteric samples. Conclusion These validation results demonstrate a high quality of the novel Anti-GBM ChLIA. Given its excellent performance compared to the corresponding ELISA, it represents a promising alternative tool for accurate anti-GBM assessment in routine diagnostic settings with the advantage of rapid turnaround time and fully automated random-access processing. Future studies will address the assay’s suitability for monitoring anti-GBM levels during follow-up.