Microhematuria: Updated Guidelines From the American Urological Association

Microhematuria and gross hematuria account for more than 1 in 5 urology evaluations; at least 2.4% of healthy people have microhematuria. Although the malignancy risk with gross hematuria is high enough to require evaluation with cystoscopy, upper urinary tract imaging, and urinary cytology, the extent of evaluation needed for microhematuria is less certain. In a series of patients with microhematuria and risk factors for bladder cancer, only 23% received imaging and 13% received cystoscopy. The American Urological Association (AUA) has published amended guidelines for the evaluation of microhematuria. Recommendations are based on limited evidence including expert recommendations.

Microhematuria is defined as 3 or more red blood cells per high-power field (RBCs/HPF) on microscopic urinalysis. Urine dipstick testing alone is insufficient for diagnosis, and microscopic urinalysis should be obtained if there are findings of trace blood or greater.

The specimen should be collected from a clean-catch midstream void. Repeat urinalysis should be considered if there is concern for contamination, such as a large number of squamous cells present in the sample. A catheterized specimen can be considered if an abnormality, such as vaginal atrophy or pelvic organ prolapse, increases the risk of contamination.

In patients with microhematuria, history and physical examination should focus on signs of genitourinary cancer, kidney disease, and gynecologic diseases. Evaluation is the same in patients taking anticoagulant or antiplatelet agents.

A catheterized urine specimen and pelvic examination can be helpful in differentiating urologic and gynecologic bleeding. If a gynecologic or nonmalignant urologic cause (eg, urinary tract infection, kidney stone) of microhematuria is diagnosed, a repeat microscopic urinalysis should be obtained following treatment or resolution. If microhematuria persists, the patient should be reevaluated.

If kidney disease is suspected, renal evaluation should be performed, but urologic risk stratification and evaluation should still be performed.

After the initial evaluation, patients should be categorized into low/negligible, intermediate, or high risk of genitourinary malignancy (Table 1). Previous AUA recommendations for risk stratification resulted in most patients being classified as high risk. The 2025 update further refines risk stratification. The main risk factors are age, sex, smoking history, number of RBCs/HPF in the urine sample, persistence of microhematuria, and history of gross hematuria. Additional risk factors for urothelial cancer include lower urinary tract symptoms, cyclophosphamide or ifosfamide (Ifex) chemotherapy, exposure to benzenes or aromatic amines, history of chronic catheterization or pelvic radiation therapy, and family history of urothelial cancer or Lynch syndrome.