title: Is the red cell morphology really useful to detect the source of hematuria?
abstract: Morphological analysis of urinary red blood cells by phase-contrast microscopy to identify the source of bleeding was, and still is, widely used also as a starting point for workup. To evaluate the reliability of this approach, we studied 129 outpatients presenting with persistent isolated microhematuria; 31 subjects also had mild proteinuria (1 g/day), while 21 had pathological albumin levels. All patients were followed for a period of 6 years. During this time, 6 patients underwent renal biopsy for the onset of macrohematuria episodes and proteinuria of 2-3 g/day. Glomerular bleeding was identified in only 14.7% of the patients, despite the persistent microhematuria and the presence of proteinuria or microalbuminuria. The renal origin of the urinary erythrocytes correlated with histological findings in only 2 of 6 patients with dysmorphic erythrocytes who developed proteinuria (exceeding 1 g/day), and none with isomorphic erythrocytes showed urological abnormalities. These results challenge the validity and reliability of morphological analysis to identify the source of bleeding along the urinary tract.
authors.affiliation: Institute of Internal Medicine, Division of Nephrology, University of Padua, Italy.
authors.forename: S
authors.initials: S
authors.lastname: Favaro
authors.forename: L
authors.initials: L
authors.lastname: Bonfante
authors.forename: A
authors.initials: A
authors.lastname: D'Angelo
authors.forename: A
authors.initials: A
authors.lastname: Giacomini
authors.forename: M
authors.initials: M
authors.lastname: Normanno
authors.forename: L
authors.initials: L
authors.lastname: Caló
authors.forename: V
authors.initials: V
authors.lastname: Bordin
authors.forename: D
authors.initials: D
authors.lastname: Vianello
authors.forename: A
authors.initials: A
authors.lastname: Meani
authors.forename: A
authors.initials: A
authors.lastname: Antonello
authors.forename: A
authors.initials: A
authors.lastname: Borsatti
mesh_terms: D000328:Adult; D004912:Erythrocytes / Q000473:pathology*; D005260:Female; D005500:Follow-Up Studies; D006417:Hematuria / Q000209:etiology* / Q000473:pathology; D006801:Humans; D007668:Kidney / Q000473:pathology; D007678:Kidney Glomerulus / Q000473:pathology; D008297:Male; D008858:Microscopy, Phase-Contrast; D013997:Time Factors