Clinical Trial of PLA2R-IgG4 Detection Kit (Time-resolved Fluorescence Immunoassay)

Inclusion Criteria: * PLA2R-induced membranous nephropathy group 1. Pathological examination showed that patients with membranous nephropathy were positive for PLA2R by immunohistochemistry, and the symptoms were not completely relieved; (24 h urine protein quantification\<0.3g or urine protein /creatinine (uPCR)\<300mg /g is regarded as complete remission) 2. In patients with nephrotic syndrome (serum albumin ≤ 30.0g /L, clinical manifestations show moderate to large amount of proteinuria (urine protein\>3.5g /L or urine protein /creatinine ratio ≥ 3500mg /g), and their serum anti PLA2R antibody detection shows positive. * Secondary membranous nephropathy group Patients in nephrology department who have ruled out primary membranous nephropathy. the patient has the remaining serum samples of normal test, and the serum volume of the sample is not less than 1ml. Exclusion Criteria: 1. The amount of centrifuged serum sample after blood collection is less than 1ml or the amount of residual serum in normal test is less than 1ml; 2. Non-serum samples, plasma samples; 3. Patients with mental or cognitive disorders; 4. No samples with definite clinical diagnosis; 5. Samples with incomplete information.