Glomerular versus extraglomerular hematuria, which statement is true?

• A. Glomerular hematuria shows RBC casts with dysmorphic RBCs; extraglomerular shows normal RBC morphology with no casts or proteinuria
• B. Glomerular hematuria shows RBC casts; extraglomerular shows RBC casts
• C. Glomerular hematuria has normal RBC morphology
• D. Extraglomerular always has proteinuria

Answer: (A)

The difference between glomerular and extraglomerular hematuria is reflected in the urine cells and the presence of casts and protein in the urine. When bleeding originates in the glomerulus, the red blood cells are damaged as they pass through the damaged capillary wall, so they become dysmorphic. They also tend to form or be found with red blood cell casts in the tubules because the cells are shed into the tubular lumen and trapped in protein matrix. Protein leakage is common because the glomerular barrier is disrupted.

Bleeding from the urinary tract outside the glomerulus gives you red blood cells that usually look normal, there are no red blood cell casts, and protein in the urine is not expected unless there is another kidney issue.

So the statement that best fits is that glomerular hematuria shows dysmorphic red blood cells with RBC casts, while extraglomerular bleeding shows normal red blood cell morphology with no casts or proteinuria.