[Discriminant analysis of clinical markers before renal biopsy in patients with IgA nephropathy]

Discriminant analysis of clinical markers before renal biopsy in patients with IgA nephropathy is described. Sixty eight patients with IgA nephropathy (IgA nephropathy group) and 66 patients with other chronic glomerulonephritis (non-IgA nephropathy group) were examined. The discriminant analysis was applied to separate those two groups by using twenty clinical parameters as well as binding capacity of serum IgA to the glomeruli of renal specimens. Binding of serum IgA of patients to the glomeruli obtained from patients with IgA nephropathy was performed using avidin-biotin immunofluorescence. Among twenty clinical markers, the levels of serum IgA and creatinine, and degree of microhematuria in IgA nephropathy group were significantly higher than those in non-IgA nephropathy group Furthermore, the positive incidence of serum IgA binding of IgA nephropathy group was significantly higher than that of serum IgA binding of non-IgA nephropathy group. The correct classification rate were 79.10% using five clinical markers including serum IgA, microhematuria, serum C4, quantitation of proteinuria and degree of proteinuria. It is indicated that the levels of serum IgA and the binding of serum IgA to the glomeruli were considered to be major markers for clinical diagnosis of patients with IgA nephropathy It was concluded that the discriminant analysis before renal biopsy was useful for diagnosis of IgA nephropathy.