Try not to panic *until* you get the results - should be the next day. You should also have a complete blood panel and urinanlysis done too - this will show if there's anything else "off" that could indicate liver issues.
Roxy's first BAT was Pre 43 and Post 100.9 = VERY HIGH
Try reading up on Liver Shunt and MVD so you have a better idea of what they are.
Roxy most likely has MVD.
When you get the results, come back to us and let us know what they are and what the Vet suggests, we can help guide you from our experiences