Assessment of microscopic hematuria in adults.

Microscopic hematuria, a common finding on routine urinalysis of adults, is clinically significant when three to five red blood cells per high-power field are visible. Etiologies of microscopic hematuria range from incidental causes to life-threatening urinary tract neoplasm. The lack of evidence-based imaging guidelines can complicate the family physician's decision about the best way to proceed. Patients with proteinuria, red cell casts, and elevated serum creatinine levels should be referred promptly to a nephrology subspecialist. Microscopic hematuria with signs of urinary tract infection should resolve with appropriate treatment of the underlying infection. Patients with asymptomatic microscopic hematuria or with hematuria persisting after treatment of urinary tract infection also need to be evaluated. Because upper and lower urinary tract pathologies often coexist, patients should be evaluated using cytology plus intravenous urography, computed tomography, or ultrasonography. When urine cytology results are abnormal, cystoscopy should be performed to complete the investigation.