What are the next steps in evaluating and managing a patient with abnormal urinalysis results showing occult blood and RBCs?

Management of Abnormal Urinalysis with Occult Blood and RBCs

The next step for a patient with abnormal urinalysis showing 1+ occult blood and 3-10 RBCs/HPF should be referral for urologic evaluation with cystoscopy and upper tract imaging, as this finding requires complete evaluation to rule out urinary tract malignancy. 1, 2

Risk Assessment and Classification

This urinalysis shows:

• 1+ occult blood on dipstick
• 3-10 RBCs/HPF on microscopy
• Trace ketones and trace leukocyte esterase

Based on the American Urological Association (AUA) guidelines, this patient has confirmed microscopic hematuria (≥3 RBCs/HPF). The risk stratification would depend on additional patient factors:

• Low risk (0-0.4% cancer risk): 3-10 RBC/HPF + Age <60 years (women) or <40 years (men) + Non-smoker or <10 pack-years
• Intermediate risk (0.2-3.1% cancer risk): 11-25 RBC/HPF or Age 60+ (women)/40-59 (men) or 10-30 pack-years smoking
• High risk (1.3-6.3% cancer risk): >25 RBC/HPF or Age 60+ (men) or >30 pack-years smoking 2

Evaluation Algorithm

1. Confirm true hematuria

   • This patient has both positive dipstick for occult blood and microscopic confirmation of 3-10 RBCs/HPF, meeting the AUA definition of microscopic hematuria 2
   • Rule out pseudohematuria (e.g., foods, medications)
   • Note: The American College of Physicians recommends confirming heme-positive dipstick results with microscopic urinalysis showing ≥3 RBCs/HPF before further evaluation 1

2. Initial laboratory workup

   • Complete blood count
   • Serum creatinine and BUN
   • Urine culture (especially with trace leukocyte esterase) to rule out infection 2

3. Urologic referral

   • The American College of Physicians recommends urology referral for cystoscopy and imaging in adults with microscopically confirmed hematuria in the absence of a demonstrable benign cause 1
   • This applies even if the patient is on antiplatelet or anticoagulant therapy 1

4. Imaging

   • CT Urography is the preferred imaging modality for upper tract evaluation
   • Alternative options for patients with contrast allergies or renal insufficiency include MR Urography or Renal Ultrasound 2

5. Cystoscopy

   • The AUA recommends cystoscopy for all patients ≥35 years with microscopic hematuria 2

Important Considerations

• Do not dismiss hematuria: Even if self-limited or microscopic, hematuria warrants complete evaluation as it may be the only sign of urinary tract malignancy 1, 2

• Avoid common pitfalls:

  • Do not attribute hematuria solely to anticoagulant/antiplatelet therapy without evaluation 1
  • Do not obtain urinary cytology or urine-based molecular markers in the initial evaluation 1
  • Do not dismiss microscopic hematuria as "normal" in women, as false-positive results are common but true hematuria still requires evaluation 3

• Follow-up after negative evaluation:

  • For patients with persistent asymptomatic microscopic hematuria after negative initial evaluation:
    • Low-risk patients: annual urinalysis
    • Intermediate/high-risk patients: consider urine cytology and repeat urinalysis at 6,12,24, and 36 months 2

Differential Diagnosis

While urinary tract malignancy is the most concerning potential cause, other possibilities include:

• Urinary tract infection (consider with trace leukocyte esterase)
• Urolithiasis
• Glomerular disease (though typically would have proteinuria)
• Benign prostatic hyperplasia (in male patients)
• Inflammatory conditions of the urinary tract

The presence of isomorphic (rather than dysmorphic) RBCs would suggest a non-glomerular source of bleeding, pointing more toward conditions like malignancy, stones, or infection 4.