I just had a terrible shock. My great vet told me that he is "Hanging up his Stethoscope" and pursuing some other interests! I just had him all trained too!!!
Anyway, he lives only about a half hour away and testing was no problem. Now the nearest vet will be 2+ hours away and am having trouble even getting one to return my emails. I will call tomorrow. The other vet that I sometimes use says that she is too far away to do the ACTH testing, but I see that you now say that there is a 4-hour window to spin, etc. so seems it should be okay.
Another possibility might be to trailer my horse 1 hour to the north where I might be able to get one of the vets that visit there once a week to do the testing. I'm thinking that the trailer stress might cause an inaccurate test--or is that mainly for Insulin testing? I was just looking at the Table of Contents and couldn't seem to find what I wanted.