title: Diagnostic value of urinary dysmorphic erythrocytes in clinical practice.
abstract: BACKGROUND
  In clinical practice, discriminating between glomerular and nonglomerular causes of hematuria is often difficult. Dysmorphic red blood cells (dRBC) in the urinary sediment are claimed to be effective, but the cutoff points in the literature vary. This follow-up study aimed to determine the diagnostic value of dRBC.
  
  
  METHODS
  We investigated 134 hematuria patients in the departments of nephrology and urology. To diagnose the origin of hematuria, urological and/or nephrological examination was performed and the %dRBC identified by microscopy. Follow-up was performed after 3.5 years.
  
  
  RESULTS
  The cause of hematuria was proven in 68 patients (35% glomerular; 65% nonglomerular). Patients with glomerular disease had significantly more albuminuria and dRBC than patients with nonglomerular disease, but the %dRBC ranged from 1 to 50% and no optimal cutoff could be identified. Logistic regression analysis showed that %dRBC had a predicted probability to diagnose glomerular disease of 77.9% (area under the curve, AUC, 0.85). When %dRBC was combined with other risk factors such as serum creatinine, sex, age, dipstick erythrocyte or proteinuria score and number of casts, the predictive probability increased to 90.6% (AUC 0.97). Follow-up of the included patients showed no benefit of dRBC to identify patients at risk for glomerular disease.
  
  
  CONCLUSIONS
  The diagnostic value of routinely collected urinary dRBC to diagnose glomerular disease in patients presenting with hematuria is modest. However, including dRBC with other variables, such as age and erythrocyte score on dipstick testing may increase the sensitivity, but needs to be confirmed in another, preferably larger, population.
authors.affiliation: Department of Internal Medicine, Erasmus Medical Center, Rotterdam, The Netherlands.
authors.forename: Meindert J
authors.initials: MJ
authors.lastname: Crop
authors.forename: Yolanda B
authors.initials: YB
authors.lastname: de Rijke
authors.forename: Paul C M S
authors.initials: PC
authors.lastname: Verhagen
authors.forename: Karlien
authors.initials: K
authors.lastname: Cransberg
authors.forename: Robert
authors.initials: R
authors.lastname: Zietse
mesh_terms: D000293:Adolescent; D000328:Adult; D000368:Aged; D000369:Aged, 80 and over; D002648:Child; D002675:Child, Preschool; D004906:Erythrocyte Count / Q000379:methods / Q000592:standards; D004913:Erythrocytes, Abnormal / Q000473:pathology*; D005260:Female; D005500:Follow-Up Studies; D006417:Hematuria / Q000097:blood* / Q000175:diagnosis* / Q000473:pathology; D006801:Humans; D007223:Infant; D008297:Male; D008875:Middle Aged; D012680:Sensitivity and Specificity; D055815:Young Adult