Identification and significance of dysmorphic versus isomorphic hematuria

Hematuria may be of glomerular or nonglomerular origin. Dysmorphic erythrocytes are found in the urine of patients with glomerular bleeding, whereas isomorphic erythrocytes characterize nonglomerular or urological hematuria. Urine specimens from 100 patients with microscopic hematuria were collected: 50 had a known glomerular pathological condition and 50 had urological disease. Scanning electron microscopy of the urine specimens showed a marked difference in morphology between dysmorphic and isomorphic red blood cells. This differentiation can be made with a simpler instrument, the standard Coulter counter. Accurate prediction of glomerular versus nonglomerular hematuria was made in 97 of the 100 patients by Coulter counter analysis. The test is rapid, simple and readily reproducible. A permanent graphic record of the red blood cell morphology can be obtained for each patient. Identification of glomerular versus nonglomerular hematuria can be of practical use in the clinical management of patients.