Hi kyle6286,
It literally could be many things other than a UTI. The urinalysis should help to diagnose a UTI. A blood test is always a good idea to see the red blood cells, platelets, white blood cells, kidney and liver values, etc. When your Vet examined your Shih Tzu they should have checked his prostate and examined the genitals and belly for any signs of trauma such as bruising, purple or dark colored patches or spots, scratches, etc. Familial history is also important as blood in the urine can run in your dog’s family.
I hope it is nothing, you and your pooches will be in my thoughts.
James
