Yesterday, I caught one of my cats peeing in a box of t-shirts I was going to give away. He's been known to use a plant once in a while when it was too inconvenient to go outside or use the litter box (sometimes the bathroom door is closed for a day by accident). So, I didn't think much of him using the t-shirt box--I was just a little miffed that he ruined the shirts.

Today I noticed that one of the top t-shirts had blood spots on it that it didn't have yesterday (the shirts are all brand new, leftovers from my baseball league). In my decluttering this evening, I realized that he has definitely peed on the wall or carpet there, because I could smell it after the box was outside. The box has been sitting there for a while, so he may have used it several times before I caught him in the act. (I didn't smell it until yesterday, and since I moved the box it is stronger.)

Now because of the blood I'm concerned that the kitty has a UT problem. I'll probably take him to the vet tomorrow. But I'm wondering, how do they diagnose such a thing?

He seems normal in every way, except for the blood. All four of the other animals have had access to that box, but none of them would pee in it and none of them have bled anywhere else. (My other cat goes exclusively outside. He doesn't use the litter box unless absolutely necessary, like extremely bad weather.)

As an aside, both of my cats were overdue for their shots (>3 years) and I had them vax'd about 2 months ago. Should I be concerned about a reaction to the vaccinations? They eat Nutro dry food and always have.

Thanks!

Karen