Which findings diagnose glomerular hematuria?

• A. RBC casts & dysmorphic RBCs
• B. RBC morphology normal
• C. Proteinuria absent
• D. No RBCs

Answer: (A)

The key finding signaling glomerular hematuria is red blood cell casts together with dysmorphic red blood cells. Red cell casts form when blood enters the nephron and red cells get trapped in a protein matrix in the tubular lumen, which reflects bleeding from the nephron. Dysmorphic red cells arise because red cells are distorted as they pass through a damaged glomerular filtration barrier, indicating an origin in the glomerulus. This combination is characteristic of glomerular bleeding.

If the red cells have normal morphology, the source is more likely non-glomerular, such as the lower urinary tract. Absent proteinuria makes glomerular injury less likely, since glomerular damage usually increases permeability to proteins. No red blood cells means there’s no hematuria.