I Have A 12-13 Year Old Chihuahua/Pekingese/Shitzu Mix Who Had

I have a 12-13 year old Chihuahua/Pekingese/Shitzu mix who had lab work done this week as part of her pre-op for dental cleaning and possible extractions. Her platelet count was elevated at 502. Her globulin was just slightly elevated at 3.7. Her BUN was 52, and her Creatinine was 1.7, with a ratio of 31. Her urinalysis showed 1+ protein, 3+ occult blood, 11-20 RBCs, but no bacteria. The vet has now ordered a urine culture and had us change her diet to Hills Science k/d. Any thoughts??? Thanks.