What is the appropriate evaluation and treatment for hematuria (presence of blood in the urine)?

Evaluation and Treatment of Hematuria

A comprehensive evaluation of hematuria requires confirmation of true hematuria through microscopic examination, risk stratification based on patient factors, and appropriate diagnostic testing including imaging and cystoscopy to identify potentially life-threatening causes. 1, 2

Initial Assessment and Classification

• Confirm the presence of true hematuria with microscopic examination (≥3 red blood cells per high-power field) rather than relying solely on dipstick results, which have limited specificity (65-99%) 2, 3
• Classify hematuria as gross or microscopic, as gross hematuria carries a higher risk of malignancy (30-40%) compared to microscopic hematuria (2.6-4%) 1, 4
• Exclude benign causes including infection, vigorous exercise, menstruation, sexual activity, trauma, and medications by repeating urinalysis 48 hours after cessation of the potential cause 1, 3
• Obtain a clean-catch urine specimen, considering catheterization if necessary (especially in women or uncircumcised men with phimosis) 5, 1

Laboratory Evaluation

• Perform complete urinalysis with microscopic examination to assess:
  • Number of red blood cells per high-power field 5, 1
  • Presence of dysmorphic red blood cells or red cell casts (suggesting glomerular source) 5, 1
  • Presence of white blood cells or bacteria (suggesting infection) 5, 1
• Obtain urine culture to rule out urinary tract infection 1, 3
• Measure serum creatinine to assess renal function 1, 3
• Consider urine cytology in patients with risk factors for bladder cancer (age >40, smoking history, occupational exposures) 1, 2

Diagnostic Algorithm

Determining Source of Bleeding

• Glomerular source is likely if:

  • Significant proteinuria (>500 mg/24 hours) 5, 1
  • Dysmorphic RBCs (>80%) 5, 1
  • Red cell casts 5, 1
  • Elevated serum creatinine 5, 1

• Non-glomerular (urologic) source is likely if:

  • Normal-shaped RBCs 5, 1
  • Minimal or no proteinuria 5, 1
  • Normal serum creatinine 5, 1

Imaging Recommendations

• CT urography is the preferred imaging modality for comprehensive evaluation of the upper urinary tract, especially in high-risk patients 1, 2
• MR urography is an alternative if CT is contraindicated 1
• Renal ultrasound with retrograde pyelography can be considered if CT and MR are not feasible 1

Specialist Referral

• Urologic referral is necessary for:

  • All patients with gross hematuria, even if self-limited 5, 1
  • Patients with microscopic hematuria and risk factors (age >40, smoking history, occupational exposures) 1, 2
  • Patients with irritative voiding symptoms in the absence of infection 5

• Nephrology referral is recommended if there is evidence of glomerular disease:

  • Proteinuria 5, 1
  • Red cell casts 5, 1
  • Predominantly dysmorphic RBCs 5, 1
  • Hypertension with persistent hematuria 5

Follow-up Recommendations

• For patients with negative initial evaluation of asymptomatic microscopic hematuria:

  • Repeat urinalysis, voided urine cytology, and blood pressure determination at 6,12,24, and 36 months 5
  • Consider additional evaluation including repeat imaging and cystoscopy in patients with persistent hematuria and high suspicion for underlying disease 5

• Immediate urologic reevaluation is necessary if any of the following occur:

  • Gross hematuria 5
  • Abnormal urinary cytology 5
  • Irritative voiding symptoms in the absence of infection 5

Important Caveats

• Do not assume hematuria is due to antiplatelet or anticoagulant medications if the patient is taking them; these patients still require full evaluation 5, 1
• Do not delay urologic referral while waiting for other test results in a patient with gross hematuria 1
• Early detection of urologic malignancy significantly impacts mortality and morbidity 2
• The risk of malignancy increases with the degree of hematuria (number of RBCs per HPF) 2
• Patients with microscopic hematuria and a negative initial evaluation still have a small risk of developing significant urologic disease, necessitating follow-up 5