Evaluating hematuria in children. Where to start and how to proceed. Bleeding from somewhere along the urinary tract is not unusual in children. Of the many causes, systemic infection and trauma are among the most common. History taking and physical examination should be careful and complete, because the results obtained help direct the laboratory evaluation. Diagnostic testing always begins with urinalysis but may progress to intravenous urography, voiding cystourethrography, endoscopic procedures in the upper and lower urinary tract, sonography, arteriography, or renal biopsy. Some cases remain unexplained and require follow-up to assess renal function. 