Microscopic Hematuria

Committee Opinion 703 serves for additional reading today!

Defining Microscopic Hematuria

• 2012 American Urologic Association (AUA) criteria - 3+ RBC/high power field

• The AUA guidelines also noted that if found, recommendation for evaluation for all patients older than age 35 years

  • This evaluation includes cystoscopy and upper urinary tract imaging with CT, with the primary concern being urothelial malignancy

• The data supporting this approach was largely based on male patients - so ACOG and AUGS put together this series of recommendations thinking about the female patient 

  • As an example of how this can be so different: the CO points to a large study where 20% of urinalyses performed had microscopic hematuria, and other studies pointing to incidences between 2% and 31% – that would be a lot of studies!

• These studies do carry risks – radiation and malignancy risk, particularly for young patients.

Differential Diagnosis and Risk Factors

• ACOG points to specimen collection being potentially more challenging in women:

  • Hematuria might result from true hematuria, but also from

    • Menstruation

    • Urogenital tract atrophy

    • Pelvic organ prolapse

    • Other non-threatening urogenital diagnosis (prostatic hypertrophy in men, urethral stricture, etc). – these are much less common in women as well.

  • The primary concern with microscopic hematuria: urothelial malignancy.

    • Risk factors:

      • Male sex

      • Age over 50

      • Previous or current smoker

      • Gross hematuria

      • HIstory of pelvic radiation

    • Male sex specifically has 3.3x more new cases of bladder cancer than female sex

      • 4th most common cancer in men, while not in the top 10 cancers for women

    • Renal cancer is also 1.7x more likely in men.

When is reasonable to consider screening in women?

• Studies looking at women have found:

  • Urologic malignancy rate in women under 40 years with any microscopic hematuria was 0.02%, and older than 40 years was 0.4%

  • Urologic malignancy rate is higher in women with 25 RBCs / hpf or greater

  • Smoking also increases risk.

• Bottom line: women older than 60, with gross hematuria, and history of smoking have highest risk of urologic cancer.

  • Low risk, never smoking women, younger than 50 and fewer than 25 RBC/hpf - risk of urologic malignancy is less than 0.5%. 

• In 2020, the AUA updated their guidelines to incorporate these gender-specific screening pathways, which are helpful to recognize and be  aware of:

  • Low risk women can undergo repeat urinalysis within 6 months, or cystoscopy/renal ultrasound

  • Intermediate risk women should undergo cystoscopy and renal ultrasound

  • High risk should undergo cystoscopy and CT urogram

• Of course, keep your local urogyn / urologist aware of any patient for whom you have concern based on risk factors to discuss evaluation for urothelial cancers.

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AUA/SUFU 2020 Microhematuria Algorithm