My Mac was sent to a Specialty Clinic years ago for a mystery ailment that had him losing weight, not eating or drinking, and my vet wanted his liver checked, also. They, too, wanted to do nothing but an invasive procedure, which I beleived would kill him. They refused to do a needle biopsy, so I left their office with some sub-q fluids and antibiotics. I started force feeding and watering him as well as giving him the meds. Two days later he started eating and drinking on his own and within 4 days he was back to normal! I hate those Specialty Cinics!