Im on the interview trail right now. One place showed me one slide which I think he just wanted to show me as a fun case but he was also probably testing my thinking a little bit. A different place, I looked at a couple of cases that the pathologist was finishing up from that day that he hadnt quite decided how to sign out (they were not zebras by any stretch of the imagination). At another place, I sat in on a conference where a handful of pathologists showed each other their challenging cases from the day and I gave my input on them.
So all in all, I havent really had a slide test yet. However, a friend of mine who is interviewing in another part of the country did have a formal slide test. It turned my friend off to that group.