you can put the animal under anesthesia (theoretically, although, probably not a good anesthetic candidate) and go in for an ultrasound guided biopsy of the liver, follwed by a good, clean blood draw and submit it for analysis by a pathologist. im in veterinary medicine (normally i work in emergency/critical care, but i dabble in relief work for different herp vets around my city. we just submitted a sample from an ball python that we just lighly knocked out with isofluorane) one of the doctors here that ive done relief with in herp medicine is doing extensive research into ibd.