What is the workup for hematuria (blood in urine)?

Diagnostic Workup for Hematuria

The diagnostic workup for hematuria should include confirmation of persistent hematuria with repeated urinalysis, risk stratification based on patient factors, appropriate imaging studies based on risk category, and referral for cystoscopy, with nephrology consultation for patients with significant proteinuria. 1

Initial Evaluation

1. Confirmation and Classification:

   • Repeat urinalysis to confirm persistence of hematuria
   • Classify as microscopic (>3 RBC/HPF) or macroscopic (gross/visible)
   • Urine culture to rule out infection 1

2. Laboratory Assessment:

   • Complete blood count
   • Renal function tests (urea, creatinine)
   • Evaluation of proteinuria (>300 mg/dL requires nephrology referral) 1
   • Urine cytology for high-risk patients or those with irritative voiding symptoms 1

Risk Stratification

Categorize patients into risk groups based on:

• High-risk factors 1:

  • Age (women ≥50 years, men ≥40 years)
  • Smoking history >30 pack-years
  • Gross hematuria or >25 RBC/HPF
  • History of pelvic radiation
  • Chronic urinary infections
  • Occupational exposures (dyes, chemicals)
  • Family history of renal cell carcinoma

• Important note: Risk of malignancy with gross hematuria is >10%, warranting prompt urologic referral 2

Imaging Studies

Select imaging based on risk category:

• High-risk patients:

  • CT urography (92% sensitivity, 93% specificity) 1
  • Consider MR urography if renal insufficiency or contrast allergy present

• Low-risk or young patients:

  • Renal ultrasound (50% sensitivity, 95% specificity) 1

Specialist Referrals

• Urology referral for:

  • All patients with gross hematuria
  • High-risk patients with microscopic hematuria
  • Persistent microscopic hematuria after negative initial evaluation 1, 2

• Nephrology referral for:

  • Significant proteinuria (>1g/day)
  • Signs of glomerular disease
  • Impaired renal function 1

Advanced Diagnostic Procedures

• Cystoscopy:

  • Recommended for all patients with persistent microscopic hematuria
  • White light cystoscopy is standard (blue light not recommended for initial screening) 1

• Additional studies when indicated:

  • Retrograde pyelography to evaluate for ureteral abnormalities
  • MAG3 renal scan with diuretic renography for functional assessment 1

Common Pitfalls to Avoid

• Assuming benign cause without complete evaluation in high-risk patients 1
• Using inadequate imaging (e.g., ultrasound alone) in high-risk patients 1
• Dismissing microscopic hematuria in patients with overactive bladder symptoms 1
• Sex disparities in referral patterns (refer regardless of sex) 1
• Delaying evaluation >9 months in patients with hematuria (associated with decreased survival in those with bladder cancer) 1

Follow-up and Monitoring

• Immediate reevaluation if:

  • Macroscopic hematuria appears
  • Significant increase in microscopic hematuria
  • New urological symptoms develop 1

• For glomerular disease:

  • Close monitoring of renal function, electrolytes, and urinalysis
  • Strict blood pressure control (target ≤125/75 mmHg) 1