RESUMO
PURPOSE: This study was undertaken to elucidate the usefulness of urinary betaig-h3 concentrations in differential diagnosis of isolated microscopic hematuria patients. METHODS: Seventy-seven patients, in whom renal biopsy was performed due to microscopic hematuria without proteinuria, were enrolled. The patients were divided into two groups, IgAN group (patients with IgA nephropathy, N=37) and NM group (patients with normal or minor change on renal biopsy, N=40), and the clinical characteristics and laboratory findings were compared between the two groups. TGF-beta and betaig-h3 concentrations in urine were determined by ELISA and were compared between the two groups. To establish the optimal cut-off value of betaig-h3/creatinine (Cr) ratio for the diagnosis of IgA nephropathy, a receiver operating characteristic curve was constructed and the sensitivity and specificity were calculated. RESULTS: A comparative analysis revealed no significant differences in age and sex ratio between the two groups. There were no differences in serum IgG, IgA, IgM, C3, and C4 levels between the two groups. The urinary betaig-h3/Cr ratio was significantly higher in the IgAN group compared to the NM group (6.632.6 vs. 4.462.6 ng/mg, p0.05). A cut-off betaig-h3/Cr ratio 4.5 has a sensitivity of 85.0% and a specificity of 77.8%. CONCLUSION: The urinary betaig-h3/Cr ratio was a good predictor for the diagnosis of IgA nephropathy. Therefore, renal biopsy should be considered in isolated microscopic hematuria patients with high urinary betaig-h3/Cr ratio.