I cannot say for certain. My Bella was treated once for UTI. I paid the $65.00 and collected the sample myself. She was being given Bentonite powder, "Animin" a rich mineral supplement and the urine had small amounts of crystal's. I told the doctor.. I felt it was related, I am not certain. If your giving your dog supplements, like Montmorillonite powder with 72 trace elements every day, I cut back to 2 times per week, told the vet. yesterday to check out my findings and give me the Keflex next time "if" it happens again, without test number 2, office visits and so on. I am not playing that game with him or anybody else, rock's cause crystals and bentonite is crushed lava volcano rocks.. He agreed to give the antibiotics for $11.00 for a week. Check it out. I am sorry you had to spend $500.00, that is not fair, for something silly, that can be fixed at the; "fish store" if you know the dosage..