Dysmorphic red blood cells (RBCs) in urine are abnormally shaped red cells that typically indicate bleeding from the glomeruli (the kidney’s filtering units). Their distorted appearance results from passage through a damaged glomerular basement membrane. Finding dysmorphic RBCs suggests a glomerular source of hematuria (e.g., glomerulonephritis) and usually prompts evaluation for proteinuria, renal function tests, and nephrology assessment.

Red blood cells in urine (hematuria) warrant concern if you see red or cola‑colored urine, if blood persists on repeat testing, or if it’s accompanied by pain, fever, burning, clots, swelling, unexplained weight loss or anemia. Risk factors like older age or smoking increase concern. Seek urgent care for heavy bleeding, clots, dizziness or low urine output; otherwise arrange prompt evaluation by your doctor or a urologist.

Dimorphic RBCs mean two distinct red blood cell populations seen on a blood smear—differing in size and/or hemoglobin content (for example, microcytic hypochromic cells alongside normocytic or macrocytic cells). This pattern suggests mixed causes of anemia (e.g., iron deficiency plus megaloblastic anemia), recent transfusion, or evolving treatment response, and warrants further tests like reticulocyte count, iron studies, and B12/folate assessment.

Normally up to 0–3 red blood cells per high-power field (RBCs/HPF) on microscopic urinalysis is considered within normal limits. More than 3 RBCs/HPF—or any visible (gross) blood—suggests hematuria and warrants repeat testing and further evaluation for urinary tract infection, stones, kidney disease, or other causes, including clinical follow-up if persistent.

Red blood cells in urine (hematuria) can result from cancers of the urinary tract, most commonly bladder cancer and renal (kidney) cell carcinoma. Urothelial carcinomas of the renal pelvis and ureter and, in men, prostate cancer can also produce hematuria. Less commonly, metastatic tumors invading the urinary tract cause bleeding. Any unexplained hematuria warrants urgent medical evaluation.

Treatment of red blood cells in urine (hematuria) focuses on identifying and managing the underlying cause. Initial steps include repeat urine testing, microscopy, culture, imaging (ultrasound or CT) and cystoscopy when indicated. Treat infections with antibiotics, manage stones, adjust anticoagulants, and treat glomerular disease (blood-pressure control, specific immunotherapy). Refer to urology/nephrology and seek urgent care for gross hematuria, clots, fever, or severe pain.