What is the next step in management for a patient with microscopic hematuria on urinalysis?

Management of Microscopic Hematuria on Urinalysis

For patients with microscopic hematuria on urinalysis, a risk-stratified evaluation is required, including confirmation with microscopic examination, assessment of risk factors, and appropriate imaging and specialist referrals based on risk category. 1

Initial Evaluation

• First step: Confirm microscopic hematuria with microscopic examination of urinary sediment (not just dipstick testing) 1
• Obtain complete blood count, serum creatinine, BUN, and urine culture if infection is suspected 1
• Assess for risk factors for urinary tract malignancy:
  • Age >60 years
  • Male gender
  • Smoking history
  • Exposure to industrial chemicals
  • Family history of renal cancer
  • History of pelvic radiation 1

Risk Stratification

The American Urological Association defines three risk categories for patients with hematuria 1:

1. Low risk: 0-0.4% risk of malignancy
2. Intermediate risk: 0.2-3.1% risk of malignancy
3. High risk: 1.3-6.3% risk of malignancy

Risk assessment is based on factors such as age, smoking history, and RBC count 1.

Management Algorithm

Step 1: Rule out benign causes

• Urinary tract infection (treat with appropriate antibiotics)
• Menstruation in women
• Vigorous exercise
• Trauma
• Recent urologic procedures 2

Step 2: Evaluate for glomerular vs. non-glomerular causes

• Glomerular hematuria: Often associated with proteinuria, RBC casts, dysmorphic RBCs
• Non-glomerular hematuria: Normal RBC morphology, no casts 3

Step 3: Risk-based evaluation

For low-risk patients:

• Annual urinalysis follow-up 1
• Consider renal ultrasound as initial imaging 1, 2

For intermediate/high-risk patients:

• Imaging of the upper urinary tract:
  • CT Urography (preferred): 92% sensitivity, 93% specificity for detecting stones, malignancy, and structural abnormalities 1
  • MR Urography: Alternative if contrast allergy or renal insufficiency exists 1
  • Renal Ultrasound: Alternative, especially in younger patients (50% sensitivity, 95% specificity) 1
• Urology referral for cystoscopy 1, 2
• Urine cytology and repeat urinalysis at 6,12,24, and 36 months 1

Step 4: Specialist referrals

• Urology referral indicated for:

  • Persistent hematuria after treatment
  • Gross hematuria
  • Age >60 years with unexplained hematuria
  • Recurrent UTIs 1

• Nephrology referral indicated for:

  • Suspected glomerular disease (especially with proteinuria)
  • Continuously increasing urinary albumin levels
  • Continuously decreasing eGFR
  • eGFR <30 mL/min/1.73 m² 1

Important Considerations

• Microscopic hematuria most commonly has benign causes, but malignancy must be ruled out, especially in high-risk patients 2
• If initial evaluation with ultrasound and cystoscopy is negative, consider follow-up in 3 months to check for persistence 4
• "Idiopathic microscopic hematuria" accounts for approximately 80% of patients with asymptomatic hematuria after thorough evaluation 5

Common Pitfalls to Avoid

• Relying solely on dipstick testing without microscopic confirmation can lead to inaccurate diagnoses 1
• Assuming hematuria is always benign can result in missed diagnoses of underlying kidney disease or malignancy 1
• Delaying or deferring investigation of microscopic hematuria may allow significant disease processes to progress 6
• Failure to repeat urinalysis after treatment of infection to confirm resolution 1

Remember that the risk of malignancy with microscopic hematuria is significant, especially in high-risk populations, and warrants thorough evaluation rather than watchful waiting alone.