Blood in urine in a 2yr old?

Question

i took my 2yr old son to the doctor last week for stomach pains, loss of appetite, fever, and dark green/black stool. They checked his urine cause of his stomach pain and found he has blood in his urine. She tested for bladder infection and such but ruled it out cause there was no sign of infection. So they sent it elsewhere to get a 2nd opinion I assume.

Anyways my question is what could the the causes of blood in urine if infection has been ruled out?

Answer 1

could be interior bleeding