I don't know much about FIV, but unfortunately, the FIP-ELISA-test isn't very realiable. It only says if there are anti-bodies against corona-viruses or not, but not if it's the corona virus that causes FIP or another one.

I'll go and try to find a link for you and keep Bramble in my thoughts... I once had a cat with FIP and I really really hope it's not that!

But what is it that makes your vet think it could be FIV or FIP? Does she have any more symptoms?

Kirsten