What Causes The Dark Yellowish Color Urine With Blood?

HI, my husband couple days ago in the morning when he went to pee, along with the urine he had some coagulant blood- a small size one. After that day he says that every time he goes to pee, the urine color is dark yellowish color. He doesn t complain for any pain but he says that he has that light burning sensation in the tip of his penis during the urination. Today he was saying that he has a little lower back pain thats all. I m concern about it, and keep telling him to go and see the doctor, but he says is not such a big deal. would you please help us? Every suggestion will be very appreciated by us. Thank you.