It is SO hard to not understand what is wrong. But it sounds like the vet did what she could. I can tell you that Mr. Meow has "something" the vet feels and we DID do the xray, and it is inconclusive....so if the vet felt it would stress him out, then I would just wait and see. (Mr. Meow is a typical Ragdoll....you can do ANYTHING to him without upsettinghim)

I also learned something recently that I never realized. 75% of an organ must be bad in order for the enzyme levels to show anything. And here all this time I thought by doing blood tests we could catch things early.

If at all possible, you might want to consider confining Ripley for a little while so that he can have his litter box close to him. It would save a lot of hard feelings caused by him missing the box (be it on purpose or by accident.)