
Am Fam Physician. 2021;104(6):655-657
Author disclosure: No relevant financial affiliations.
Key Points for Practice
• Consider repeating urinalysis in women found to have microscopic hematuria associated with UTI following successful treatment.
• With microscopic hematuria in patients at low risk of cancer, performing repeat urinalysis at six months is a reasonable alternative to imaging and cystoscopy.
• Although gross hematuria is strongly associated with malignancy, microscopic hematuria is more common and has a lower malignancy risk.
From the AFP Editors
Previous guidelines from the American Urological Association (AUA) recommended that all patients with microscopic hematuria be fully evaluated for urinary tract cancer without regard to the patient's risk of malignancy. Although this strategy results in the fewest missed cancers in modeling studies, it is costly, increases patient risk, and can result in overdiagnosis. The AUA released an updated guideline for risk-based evaluation of microscopic hematuria.
Defining Microscopic Hematuria
The AUA defines microscopic hematuria as three or more red blood cells per high-power field (RBC/HPF) on urine microscopy. A threshold between three and 10 RBC/HPF has the highest sensitivity for detecting bladder cancer and the lowest negative likelihood ratio. A single urinalysis is sufficient because 95% of microscopic hematuria is detected in one sample. Because at least 20% of positive dipstick tests for blood have no red blood cells on subsequent urine microscopy, any positive dipstick should be confirmed.
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