Urinalysis for the diagnosis of glomerulonephritis: role of dysmorphic red blood cells

Background: Dysmorphic red blood cells (dRBCs) on urine microscopy have been associated with glomerulonephritis (GN). We assessed the prevalence and ability of dRBCs to differentiate GN from other kidney diseases. Methods: Adult patients with kidney biopsy performed between 2012 and 2015 at a single center who had a concurrent urinalysis were retrospectively studied. The association of ≥25% dRBCs with the presence of glomerular pathology was assessed. Univariate and multivariate logistic regression were performed on significantly associated variables. Results: The mean age of the 482 eligible subjects was 55 years and 47.7% were female. Overall, 173 (35.9%) had 10 versus ≤10 (P  10 RBCs/high-power field) and proteinuria performed just as well as dRBCs plus proteinuria to predict underlying GN. A model based on the degree of hematuria and proteinuria found on urinalysis was able to predict the presence of GN.