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).
According to quantity
- Macroscopic hematuria (gross hematuria)
- Microscopic hematuria 
According to the occurrence during voiding
- Initial hematuria
- Terminal hematuria
- Total hematuria
- Painless hematuria (asymptomatic hematuria)
According to origin
- Nephritic syndrome
- Isolated hematuria: the presence of RBCs in the urine with no other urinary abnormalities (e.g., changes in urine protein, serum creatinine, or blood pressure)
- Malignancy: especially if otherwise asymptomatic
- Coagulation disorders
Urinary tract obstruction
- Benign prostatic hyperplasia
- Congenital anomalies
- Renal papillary necrosis
- Trauma (e.g., urethral, bladder, ureteral, or renal injury) 
- Personal and family history
- Medication: e.g., anticoagulants, nephrotoxic agents
- Travel history: especially areas endemic for Schistosoma haematobium or tuberculosis
- Additional urinary symptoms
- Additional nonurinary symptoms
- Urine dipstick: detects heme in urine (high sensitivity, low specificity)
Urine sediment: Confirm hematuria with microscopy (≥ 3 RBCs/HPF).
- If RBC casts and proteinuria are present: Evaluate for .
- If the morphology of RBCs is normal: Evaluate for nonglomerular causes (e.g., coagulation disorders, kidney stones, malignancy).
- Urine that is positive for heme on dipstick but shows no RBCs on microscopy indicates hemoglobinuria or myoglobinuria.
- In hemoglobinuria and myoglobinuria, the urine remains pigmented after centrifugation because the pigments are dissolved in the urine and do not settle at the bottom like RBCs in hematuria.
- Urine culture: Perform if clinical signs of infection exist or dipstick is positive for WBCs (pyuria) and/or leukocyte esterase (see “ ”).
Findings of glomerular and nonglomerular hematuria
|Glomerular vs. nonglomerular hematuria |
|Glomerular hematuria||Nonglomerular hematuria|
|Color (macroscopic)|| || |
|RBC morphology|| || |
|RBC casts|| || |
|Clots|| || |
|Proteinuria|| || |
Diagnosis of underlying disease
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- Beeturia: red discoloration of urine after eating beetroot
- Drug-induced urine discoloration
The differential diagnoses listed here are not exhaustive.