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Abstract: TH-PO1007

High Serum IgA/C3 Ratio Better Predicts a Diagnosis of IgA Nephropathy Among Primary Glomerular Nephropathy with Proteinuria ≤1 g/d: An Observational Cross-Sectional Study

Session Information

Category: Glomerular Diseases

  • 1203 Glomerular Diseases: Clinical, Outcomes, and Trials


  • Zhang, Jun, Department of Nephrology, The Third Affiliated Hospital of Sun Yat-Sen University, Guangzhou, China

Serum immunoglobulin A (IgA)/C3 ratio is considered to be an effective predictor of IgA nephropathy (IgAN).This study aims to explore the diagnostic value of serum IgA/C3 ratio in IgAN among primary glomerular nephropathy in China.


We recruited 1095 biopsy-diagnosed primary glomerular nephropathy patients including 757 IgAN patients and 338 Non-IgAN patients. Social demography, serum immunological indexes and other clinical examinations were measured. IgAN cases were propensity scored matched (PSM) to Non-IgAN cases on the logit of the propensity score using nearest neighbor matching in a 1:1 fashion with a caliper of 0.02 with no replacements, according to age, gender, BMI, proteinuria and eGFR.


We found that, both in the full cohort and PSM cohort, serum IgA/C3 ratio in IgAN group was significantly higher than those in Non-IgAN group. The same results were also obtained at different levels of proteinuria and renal function stratification. In the PSM cohort, there was no difference in IgA/C3 ratio in patients with IgAN between different proteinuria groups and different CKD groups. The area under the ROC curve (AUROC) for IgA/C3 ratio in distinguishing IgAN among primary glomerular disease was 0.767 in the full cohort and 0.734 in the PSM cohort. The highest AUROC of IgA/C3 ratio was in the proteinuria≤1 g/d group (0.801 in the full cohort, and 0.803 in the PSM cohort); however, there was no difference between all the CKD groups. Meanwhile, the diagnose accordance rate of diagnostic of IgAN among all those patients with IgA/C3 ratio > 3.5304 was as high as 92.02% in the full cohort. Multivariate logistic regression analysis showed, IgAN was independently correlated with age, albumin, CKD 2 stage and CKD 3-5 stage (versus CKD 1 stage) and IgA/C3 ratio.


The present study provided clear evidence that IgA/C3 ratio is an effective predictor of IgA diagnosis, especially in patients with proteinuria ≤ 1g/d. In order to study the effectiveness of this biomarker and to determine a standardized cut-off value, large-scale studies are necessary.