Red cell morphology as a diagnostic aid in hematuria.

Dried smears of urinary sediment stained with Wright's stain were examined and compared in 20 selected patients with hematuria. In ten patients with microscopic hematuria and glomerular lesions demonstrated by renal biopsy, the urinary red cells were characteristically dysmorphic and hypochromic. This was distinctly different from the red cell morphology in ten patients with nonglomerular causes of hematuria, which was more like peripheral blood. The pathogenesis of the changes in red cell morphology seen in glomerular hematuria is unknown, but it appears not to be due to the urine composition per se. It is concluded that with some limitations, this simple, noninvasive technique may be useful in identifying a source of bleeding in the workup of hematuria.