Blood in urine (hematuria) is detected on dipstick and reflects the presence of red blood cells, hemoglobin, or myoglobin. True microscopic hematuria is defined as >2–3 RBCs per high-power field, confirmed on repeat urinalysis.
Key distinction—source of bleeding:
- Dysmorphic RBCs: Suggest a glomerular source (e.g., IgA nephropathy, Alport syndrome)
- Nondysmorphic RBCs: Suggest a lower urinary tract source (e.g., stones, infection, malignancy)
Clinical significance:
- Gross hematuria: High-risk finding (>10–25% malignancy risk); warrants urgent evaluation
- Microscopic hematuria: Lower but meaningful risk (0.5–5%, higher in high-risk patients) For healthy individuals: Confirm dipstick findings with microscopy. Exclude transient causes (exercise, menstruation, recent sexual activity) before pursuing workup.


