Did your vet do only a biopsy or did he do exploratory surgery? If doing a minimally invasive biopsy, it does not surprise me that he did not find a shunt because it was probably done either by ultrasound-guided needle biopsy or minimally invasive surgery (laparoscopy). Larger samples and such and more digging around would be done with full open exploratory surgery - a much more invasive procedure. It's been many years since I talked about these issues with Daisy's doctors but from what I recall, they were different surgical procedures depending on the goal.
I don't necessarily agree that there is a problem that your vet did not do BATs. Blood work and clinical findings are read as a whole in determination of the next steps. When Barney had a persistent elevation of a certain liver enzyme, the next step was a biopsy if the mild elevation of this certain liver enzyme continued. No one talked about BATs. This was a course of action recommended by my general vet. I got a second opinion from Daisy's internist and he said Barney's biopsy was not warranted just yet. They determined this based on Barney's blood work as a whole, his veterinary history, his clinical presentation upon physical examination, his current state of being, and other factors.
I see no reason why you could not ask your vet about some of the things other posters have suggested. Personally, I'd be making sure I consulted with a bd. cert. vet internist as you will cut to the chase faster and get the answers to all of it really quickly. I like to think of my general vet as Grand Central Station. Sometimes I get off the train there, and sometimes I need to change trains and go somewhere else. The thing is, my general vet has all the directions I need to choose the right train and to help me to get to my destination. Sometimes I know what to do based on my experience, but most of the time I don't. Corny analogy but true, I probably should not share that thought with my vet though.
