What is the evaluation and management approach for a patient with hematuria (presence of blood in urine) or significant microscopic hematuria (presence of red blood cells in urine)?

Evaluation and Management of Hematuria: Urine Blood vs Urine RBC

Hematuria, whether gross (visible blood in urine) or microscopic (≥3 red blood cells per high-power field on microscopic evaluation from 2 of 3 properly collected specimens), requires thorough evaluation to rule out serious underlying conditions including malignancy. 1, 2

Definition and Initial Assessment

• Microscopic hematuria is defined as ≥3 red blood cells per high-power field (RBC/HPF) on microscopic evaluation of urinary sediment from 2 of 3 properly collected specimens 1
• Dipstick positivity for blood should always be confirmed with microscopic evaluation due to limited specificity (65-99%) 1
• For high-risk patients, a single urinalysis with ≥3 RBC/HPF may warrant full evaluation 3
• The prevalence of asymptomatic microscopic hematuria varies from 0.19% to 21%, with higher rates in older men 1

Risk Stratification

• Risk factors for significant urologic disease include:

  • Age ≥60 years 3
  • Male sex 3
  • Smoking history 1, 3
  • Degree of hematuria (>25 RBC/HPF indicating higher risk) 2
  • History of gross hematuria 2
  • Irritative voiding symptoms 3

• Gross hematuria carries >10% risk of malignancy and requires prompt urologic referral 4

Diagnostic Approach

Initial Evaluation:

• Confirm microscopic hematuria with microscopic examination of urinary sediment 1
• Assess for dysmorphic red blood cells or red cell casts (suggesting glomerular origin) 2, 5
• Test for proteinuria (better predictor of glomerular disease than dysmorphic RBCs) 5
• Measure serum creatinine 2
• Rule out benign causes:
  • Urinary tract infection
  • Exercise
  • Sexual activity
  • Viral illness
  • Trauma 3

Imaging and Specialized Testing:

• CT urography is preferred for comprehensive evaluation of the upper urinary tract in high-risk patients 2, 3
• Renal ultrasound may be used for initial screening in low-risk patients 2
• MR urography for patients who cannot receive CT contrast 2
• Cystoscopy is recommended to evaluate the lower urinary tract, especially in high-risk patients 2, 3
• Urine cytology may be considered with risk factors for carcinoma in situ or irritative voiding symptoms 3

Age-Based Approach:

• Patients ≤40 years with microscopic hematuria: non-contrast CT or ultrasound; add cystoscopy if gross hematuria 6
• Patients >40 years: pre- and post-contrast CT and cystoscopy 6

Important Considerations

• Even with high percentage of dysmorphic RBCs (≥40%), urological evaluation should not be omitted as 34% of such patients may have urological disease, including malignancy 5
• Do not assume anticoagulation therapy or BPH is the cause of hematuria without proper evaluation 2
• Tea-colored urine with proteinuria, red blood cell casts, and deformed red blood cells suggests glomerular source 1
• Early detection of urologic malignancy significantly impacts mortality and morbidity 3

Follow-Up Recommendations

• For patients with persistent hematuria after negative initial evaluation:
  • Repeat urinalysis, urine cytology, and blood pressure determination at 6,12,24, and 36 months 2
  • Consider nephrology referral if hematuria persists with development of hypertension, proteinuria, or evidence of glomerular bleeding 2
  • Further workup is warranted if the patient develops gross hematuria, significant increase in microscopic hematuria, or new urologic symptoms 3

Common Pitfalls to Avoid

• Relying solely on dipstick testing without microscopic confirmation 1
• Assuming hematuria in patients on anticoagulation does not require evaluation 2, 7
• Omitting cystoscopy in younger patients with microscopic hematuria 2
• Neglecting evaluation of microscopic hematuria due to its high prevalence 8
• Assuming that dysmorphic RBCs (≥40%) rule out urological disease 5