How do I manage a patient with hematuria (presence of erythrocytes in urinalysis)?

Management of Erythrocytes in Urinalysis

When you find erythrocytes on urinalysis, first confirm true hematuria with microscopic examination showing ≥3 RBCs per high-power field, then systematically exclude benign causes before proceeding to risk-stratified urologic evaluation. 1, 2

Step 1: Confirm True Hematuria

• Never rely on dipstick alone – dipstick has only 65-99% specificity and produces false positives from myoglobin, hemoglobin, concentrated urine, or menstrual contamination 1, 3
• Obtain microscopic urinalysis on a properly collected clean-catch midstream specimen showing ≥3 RBCs/HPF to confirm true hematuria 1, 2
• Note: 0-2 RBCs/HPF is within normal range and does not warrant urologic workup 3

Step 2: Exclude Benign Transient Causes

If a benign cause is suspected, repeat urinalysis 48 hours after the cause resolves: 2

• Menstruation – repeat UA after menses ends 1, 2
• Vigorous exercise – repeat 48 hours after cessation 1, 2
• Sexual activity or trauma – repeat after resolution 2, 3
• Viral illness – repeat after illness resolves 1, 2

If urinary tract infection is suspected: 1, 2

• Obtain urine culture before starting antibiotics 1, 3
• If culture positive, treat appropriately and repeat urinalysis 6 weeks after treatment completion to document resolution 2, 4
• Persistent hematuria after UTI treatment requires full urologic evaluation 2

Step 3: Determine Glomerular vs. Non-Glomerular Source

Examine urinary sediment for glomerular indicators: 2, 3, 4

Glomerular source (refer to nephrology):

• Dysmorphic RBCs >80% 2, 3, 5
• Red blood cell casts (pathognomonic for glomerular disease) 1, 2, 4
• Significant proteinuria >500 mg/24 hours 1, 2, 4
• Elevated serum creatinine or declining renal function 2, 4
• Tea-colored or cola-colored urine 3

Non-glomerular source (proceed to urologic evaluation):

• Normal RBCs >80% 3
• Bright red blood 3
• Absence of casts, proteinuria, or renal dysfunction 2

Step 4: Risk Stratification for Urologic Malignancy

High-risk features requiring immediate complete urologic evaluation: 1, 2, 3, 4

• Age ≥60 years (males) or ≥60 years (females) 1, 2
• Gross hematuria (30-40% malignancy risk) – even if self-limited 1, 3
• History of gross hematuria (odds ratio 7.2 for urologic cancer) 1
• Smoking >30 pack-years 1, 2, 3
• >25 RBCs/HPF 2
• Occupational exposure to benzenes or aromatic amines 1, 2, 3
• Irritative voiding symptoms without infection 2, 3
• History of pelvic irradiation 2
• Analgesic abuse 2

Intermediate-risk features (shared decision-making for evaluation): 2

• Women age 50-59 years or men age 40-59 years 2
• Smoking 10-30 pack-years 2
• 11-25 RBCs/HPF 2

Low-risk features (may defer immediate evaluation): 2

• Women <50 years or men <40 years 2
• Never smoker or <10 pack-years 2
• 3-10 RBCs/HPF on single urinalysis 2
• No additional risk factors 2

Step 5: Complete Urologic Evaluation (for High/Intermediate Risk)

Upper tract imaging: 1, 2, 3, 4

• Multiphasic CT urography is the preferred modality (detects renal cell carcinoma, transitional cell carcinoma, urolithiasis) 1, 2, 3, 4
• Alternative: MR urography if CT contraindicated 3
• Renal ultrasound alone is insufficient 3

Lower tract evaluation: 2, 3, 4

• Cystoscopy is mandatory for all patients ≥40 years with hematuria and any age with risk factors 1, 2, 4
• Flexible cystoscopy preferred (less pain, equivalent diagnostic accuracy) 3, 4

Laboratory testing: 2, 4

• Serum creatinine 2, 4
• Urine cytology in high-risk patients 2, 4

Step 6: Follow-Up for Negative Initial Evaluation

If complete workup is negative but hematuria persists: 1, 2, 4

• Repeat urinalysis at 6,12,24, and 36 months 1, 2, 4
• Monitor blood pressure at each visit 1, 2, 4
• Consider nephrology referral if hematuria persists with development of hypertension, proteinuria, or glomerular bleeding 1, 2, 4
• Comprehensive re-evaluation in 3-5 years if hematuria persists 2

Immediate re-evaluation warranted if: 2, 3, 4

• Gross hematuria develops 2, 3, 4
• Significant increase in degree of microscopic hematuria 2, 3
• New urologic symptoms appear 2, 3

Critical Pitfalls to Avoid

• Never attribute hematuria to anticoagulation or antiplatelet therapy alone – these medications may unmask underlying pathology but do not cause hematuria; full evaluation must proceed 1, 3
• Never ignore gross hematuria, even if self-limited – it carries 30-40% malignancy risk and requires urgent urologic referral 1, 3
• Do not screen asymptomatic patients with urinalysis for cancer detection – this is not recommended by any major health organization 1
• Always specifically ask about history of visible hematuria in review of systems – it is commonly underreported but significantly increases cancer risk 1
• Do not defer evaluation in elderly patients – males ≥60 years are automatically high-risk regardless of other factors 2, 3