What do the newest American Urological Association (AUA) guidelines recommend for asymptomatic microscopic hematuria?

AUA Guidelines for Asymptomatic Microscopic Hematuria

According to the most recent AUA guidelines, asymptomatic microscopic hematuria (AMH) should be risk-stratified, with patients categorized as low, intermediate, or high risk, with all patients ≥35 years requiring cystoscopy regardless of risk level. 1

Definition and Diagnosis

• AMH is defined as ≥3 red blood cells per high-power field (RBC/HPF) on microscopic examination of a properly collected urinary specimen in the absence of an obvious benign cause 2, 1
• Dipstick positivity alone is insufficient and requires microscopic confirmation 1
• Confirmation should be from 2 of 3 properly collected urinalysis specimens 2, 1

Risk Stratification

The AUA and Society of Urodynamics, Female Pelvic Medicine and Urogenital Reconstruction (SUFU) recommend stratifying patients into risk categories:

Risk Level	Criteria
Low/Negligible (0-0.4%)	3-10 RBC/HPF + Age <60y (women) or <40y (men) + Never smoker or <10 pack-years
Intermediate (0.2-3.1%)	11-25 RBC/HPF or Age 60+ (women)/40-59 (men) or 10-30 pack-years smoking
High (1.3-6.3%)	>25 RBC/HPF or Age 60+ (men) or >30 pack-years smoking

Risk Factors for Significant Disease

• Age >40 years (particularly >60 years)
• Male gender
• Smoking history (particularly >30 pack-years)
• Occupational exposure to chemicals or dyes (benzenes or aromatic amines)
• History of gross hematuria
• History of urologic disorder or disease
• Irritative voiding symptoms
• History of urinary tract infection
• Analgesic abuse
• History of pelvic irradiation 2, 1

Recommended Evaluation

Initial Assessment

• Complete history and physical examination
• Renal function testing (serum creatinine, BUN)
• Urinalysis with microscopy to confirm hematuria
• Assess for benign causes (infection, menstruation, vigorous exercise, etc.) 2, 1

Imaging

• CT Urography is the preferred imaging modality for upper tract evaluation 2, 1
• Alternative imaging options for patients who cannot undergo CTU:
  • MR Urography (for patients with contrast allergy or renal insufficiency)
  • Retrograde pyelograms in combination with non-contrast CT, MRI, or ultrasound 2, 1

Cystoscopy

• All patients ≥35 years should undergo cystoscopy regardless of risk level 2, 1
• Cystoscopy is mandatory for all patients with gross hematuria, regardless of resolution 1

Follow-Up Recommendations

• For patients with negative initial evaluations but persistent AMH:

  • Low-risk patients: Annual urinalysis
  • Intermediate/high-risk patients: Consider urine cytology and repeat urinalysis at 6,12,24, and 36 months 1
  • Repeat anatomic evaluation within 3-5 years or sooner if clinically indicated 2, 1

• Immediate re-evaluation is warranted if the patient develops:

  • Recurrent gross hematuria
  • Abnormal urinary cytology
  • New irritative voiding symptoms 1

Special Considerations

• Women: The American College of Obstetricians and Gynecologists and American Urogynecologic Society recommend that low-risk, never-smoking women aged 35-50 years undergo evaluation only if they have >25 RBC/HPF 3

• Nephrology referral: Consider when there is evidence of:

  • Significant proteinuria (>1,000 mg/24 hours)
  • Red cell casts
  • Dysmorphic red blood cells
  • Renal insufficiency 2, 1

Common Pitfalls to Avoid

• Relying solely on dipstick testing without microscopic confirmation 1
• Attributing hematuria solely to smoking without thorough evaluation 1
• Inadequate follow-up of high-risk patients with negative initial workup 1, 4
• Using urine cytology for initial evaluation (not recommended by current guidelines) 1, 5
• Poor adherence to guidelines - studies show only 23.5% of patients are evaluated in complete accordance with AUA guidelines 5

By following these evidence-based recommendations, clinicians can appropriately evaluate patients with AMH to identify significant underlying conditions while minimizing unnecessary testing in low-risk individuals.