RESUMO
Objective To explore the value of serum IgA,serum C3 and IgA/C3 ratio in the diagnosis and clinical monitoring of IgA nephropathy,which provide new insight for the alternatives of renal biopsy. Methods In the first affiliated hospital of Dalian Medical University,60 patients with IgAN,60 patients with non-IgAN and 40 healthy people were detected by blood biochemical indexes and immune indexes,such as the Urea,serum IgA and serum C3,IgA/C3 ratio. According to the healthy condition and Lee grading,we divided all the 160 patients into different groups. By comparing the blood biochemical indexes and immune indexes among these different groups,we investigated the relationship between the serum IgA/C3 ratio and the IgAN.Results Firstly,the level of serum IgA and IgA/C3 were obviously different among the patients with IgAN,patients with non-IgAN and healthy people(P<0.01).Secondly,the serum IgA and IgA/C3 have high specificity and sensitivity when distin-guishing between IgAN and non IgAN. Thirdly,the level of serum IgA and IgA/C3 have significant deference be-tween the patients with Lee Ⅰ-Ⅱ grading and the patients with Lee Ⅲ-Ⅴ grading,while the level of C3 is very similar between different groups in all the three situations mentioned above. Conclusion Our research provides stronge evidence demonstrates that the level of serum IgA/C3 ratio have close relationship with IgAN and they can serve as the reference index when diagnosising and grading IgAN.