Prediction of diagnosis of immunoglobulin A nephropathy prior to renal biopsy and correlation with urinary sediment findings and prognostic grading.

Several clinical markers correlate well with the diagnosis and prognosis of IgA nephropathy (IgAN). In the present study, we re-evaluated the usefulness of these four clinical markers for prediction of the diagnosis of patients with IgAN through a comparison between many more patients with IgAN and those with other types of renal diseases. 364 patients with IgAN and 289 with other types of renal disease were examined. An analysis was performed prior to renal biopsy, using clinical markers including, serum IgA, serum IgA/C3 ratio, number of red blood cells in urinary sediments, and urinary protein. Patients with IgAN were divided into four groups according to histopathological findings. Presence of microscopic hematuria, persistent proteinuria, high serum IgA levels, and the serum IgA/C3 ratios are useful for prediction of diagnosis of IgAN and distinguishing it from other renal diseases. Blood pressure, urinary protein, serum uric acid, renal function, and urinary sediment findings may be useful for prediction of prognostic grading in patients with IgAN. (Copyright ) 2008 Wiley-Liss, Inc.