Last updated: September 6, 2022

Summarytoggle arrow icon

Hematuria, defined as the presence of red blood cells (RBCs) in the urine, can be classified according to quantity, occurrence during voiding, and origin of bleeding. In microhematuria, color changes in the urine are not clearly visible to the naked eye, and RBCs are only detectable under microscopy. Macrohematuria (gross hematuria) is visible discoloration of urine that results from frank blood. Glomerular hematuria originates from damage to the glomeruli. Nonglomerular hematuria results from damage to the kidneys or upper/lower urinary tract. If hematuria is detected, patients should undergo further evaluation (e.g., urinalysis) to determine the underlying cause. Other causes of red discoloration of the urine include myoglobinuria, porphyria, certain drugs (e.g., rifampin), and the consumption of certain foods (e.g., beetroots).

Definitiontoggle arrow icon

Classificationtoggle arrow icon

According to quantity

According to the occurrence during voiding

Gross painless hematuria is the most common clinical finding in urinary tract cancer and should be evaluated with cystoscopy.

According to origin

Glomerular hematuria

Nonglomerular hematuria

Diagnosticstoggle arrow icon

Medical history and physical examination


When hematuria (red or brown urine, positive urine dipstick) is suspected, the presence of RBCs must be confirmed with microscopic analysis of the urine sediment.

Findings of glomerular and nonglomerular hematuria

Glomerular vs. nonglomerular hematuria [3]
Glomerular hematuria Nonglomerular hematuria
Color (macroscopic)
  • Often normal
  • Sometimes light red
  • Dark red or pink urine
RBC morphology
  • Normal (isomorphic)
RBC casts
  • Sometimes present
  • Absent
  • Absent
  • Sometimes present
  • < 500 mg/day

Diagnosis of underlying disease

Differential diagnosestoggle arrow icon

  • Hemoglobinuria and myoglobinuria
    • Both conditions cause red, amber, or “Coca-Cola” colored transparent urine that remains pigmented after centrifugation.
    • Urine remains pigmented after centrifugation because the pigments are dissolved in the urine and do not settle at the bottom like RBCs in hematuria.
  • Porphyrias
  • Beeturia: red discoloration of urine after eating beetroot
  • Drug-induced urine discoloration
    • Rifampin: harmless red-orange discoloration of bodily fluids (urine, sweat, tears)
    • Phenazopyridine: orange discoloration of urine

The differential diagnoses listed here are not exhaustive.

Referencestoggle arrow icon

  1. Mount DB, Pollak MR. Molecular and Genetic Basis of Renal Disease. Elsevier Health Sciences ; 2008
  2. Sharp VJ, Barnes KT, Erickson BA. Assessment of asymptomatic microscopic hematuria in adults.. Am Fam Physician. 2013; 88 (11): p.747-54.
  3. Estrada CR. Traumatic Hematuria. In: Myers JA, Millikan KW, Saclarides TJ, eds.$Common Surgical Diseases. Springer; 2008.

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