LAUSR

Background Anti-phospholipase A2 receptor (anti-PLA2R) is a promising biomarker for diagnosis, activity evaluation, therapy monitoring, and prognostic estimation of primary membranous neuropathy (pMN). Difference in methodology may be one cause of the discrepancy in anti-PLA2R-positive percentages in reported studies. In this study, we evaluated the determination consistency of anti-PLA2R using indirect immunofluorescence assay (IIF) and enzyme-linked immunosorbent assay (ELISA). Methods A total of 113 patients with pMN, 34 with secondary membranous neuropathy (sMN), and 53 healthy control individuals were enrolled. We tested their circulating anti-PLA2R, along with other biochemical parameters, using IIF and ELISA. Results The sensitivity of anti-PLA2R for pMN was 70.8% by IIF and 67.3% by ELISA, with no statistically significant difference. The overall qualitative agreement of anti-PLA2R was 91.15% (95% confidence interval [CI], 85.91%-96.39%), and the correlation coefficient was 0.79 for IIF versus ELISA. The overall correlation coefficient of anti-PLA2R titers by IIF and concentration by ELISA was 0.85. Through ROC curve analysis, anti-PLA2R as measured by IIF and ELISA showed larger areas under the curve (AUCs) than other biochemical parameters. Conclusion ELISA shows similar performance to IIF, with the advantages of quantitative results and suitability for high throughput.