Microscopic Hematuria Evaluation

Introduction to Microscopic Hematuria

• The American College of Radiology recommends that patients without risk factors who have microhematuria attributed to menstruation do not require a complete imaging workup if the hematuria resolves after menstruation 1, 2
• Menstruation is recognized as one of several benign causes of microscopic hematuria, along with vigorous exercise, infection, trauma, and recent urologic procedures 1, 2

Diagnostic Approach

• When microscopic hematuria is suspected to be due to menstruation, a repeat urinalysis should be performed 48 hours after cessation of menstruation 3
• If the hematuria resolves after menstruation ends, no additional evaluation is warranted 3

Proper Sample Collection

• In women, obtaining a clean-catch urine specimen may be difficult during menstruation due to vaginal contamination 3
• A catheterized urinary specimen is indicated if a clean-catch specimen cannot be reliably obtained during menstruation 3
• Urethral and vaginal examinations should be performed in women to exclude local causes of microscopic hematuria 3

Evaluation Algorithm for Persistent Hematuria

• Determine if hematuria is persistent (≥3 red blood cells per high-power field) 5, 4
• Assess for risk factors for urologic malignancy (age >35 years, smoking history, occupational exposures) 1, 2
• Complete urologic evaluation including examination of urinary sediment, testing for proteinuria and urinary tract infection 3
• Radiologic imaging of the upper urinary tract and cystoscopic examination may be necessary 3, 5

Risk Stratification

• Microscopic hematuria has a low risk of malignancy (2.6% to 4%) compared to gross hematuria (30% to 40%) 1, 2

Common Pitfalls to Avoid

• Do not assume that menstruation is the cause of hematuria without proper verification through repeat testing after menstruation 3
• Do not neglect evaluation of persistent hematuria even if there is a potential benign cause like menstruation 5, 4
• Be aware that contamination from vaginal bleeding during menstruation can produce false-positive results for hematuria 3