A nurse reports that an infant has a red-stained diaper and states the infant may have hematuria. Hematuria is the presence of gross or microscopic blood in the urine. It is defined as ≥5 red blood cells per high power field (HPF) on a centrifuged urine sample. Some authors recommend that 2 of 3 urinalyses show microhematuria before an evaluation is undertaken. Hematuria is rare in newborns.