My daughter has microscopic blood cells in her urine. what could be wrong?

Urinary blood in kid: Could be urinary (bladder or kidney) infection, might be from a congenital structural or vacular abniormality of urinary tract, glomerulonephritis if accompanied by proteinuria, straining to urinate with a stool impaction or just benign (sometimes familial) microscopic hematuria. Sould be worked up with at least a kidney & bladder ultrasound, possibly cystoscopy if indicated..