EG, If you did want to have him properly diagnosed you'd have to take him off of the pred for a while or else the test results wouldn't be accurate. This is one reason why I decided to have Starr diagnosed before I started giving him the pred. At my other vets, he was on such a small doseage of pred that it did nothing for him. I've also read that over time pred dosen't work as well as it did initially. Maybe your Jimmy has something else. I hope that you'll be able to find out what his problem is and that he'll be able to get the help that he needs to stop his diarrhea and asthma problems. Good luck and please keep me updated about him.