Ah you know, it may have been the exploratory surgery, plus sending multiple samples to pathology, plus other diagnostics we did before the surgery (which would have been inconclusive), and may have also included one or two overnights - all from a specialist at a 24 hour ER clinic. I thought I remember it being explicitly not all-inclusive (i.e., piecemeal), but I could be fuzzy. Either way, the surgery itself was 1) highly invasive, so something to consider if your animal is older, and 2) definitely not in the $700 range Though I don’t remember anyone categorizing it as a small biopsy - I wonder if maybe we had different types/degrees of exploratory surgeries?
But you’re totally right that it could have also included a night or two of ER care (but that by itself would have been ~ $1000 or so, so I’d still lump most of the 6k bill into the diagnostics category).