What can dysmorphic red blood cells indicate?

Dysmorphic red blood cells in urine are indicative of glomerular bleeding. These cells undergo morphological changes as they pass through the glomerular filtration barrier, which is designed to filter blood while retaining cells and larger molecules. When there is damage to the glomeruli, such as in various forms of glomerulonephritis or other kidney disorders, red blood cells can take on abnormal shapes (dysmorphism) as they exit the glomeruli into the urine.

This finding is significant because it suggests that the source of bleeding is from the glomeruli rather than other parts of the urinary tract, such as the bladder or urethra, where red blood cells would typically retain their normal morphology. Therefore, the presence of dysmorphic red blood cells is a key diagnostic feature that helps differentiate between glomerular causes of hematuria and those that may originate from other locations within the urinary system.