I'm sorry about your Merlin! I hope you can find where his problems are coming from...But I just want to let you know that a 40 post meal for the bile acid test CAN indicate MVD. I know several yorkies who have been diagnosed with MVD with results of under 100...There's a group of very knowledgable people on this group regarding liver shunts and mvd.
http://pets.groups.yahoo.com/group/L...d_MVD_Support/
Please join this group and tell them your situation. They will be more than happy to help.