I like that they didn't ask about Carter .. it would have made it seem a little more soap opera-ish .. you know, a race for the clock to get the kidney there? I did think it was weird, though. But it worked with the episode.
Here's the Wikipedia entry for Season 15:
http://en.wikipedia.org/wiki/ER_(season_15)
Thanks for the wikipedia link. It looks like before it is all said and done we will see (or at least hear about--Cleo) everyone but Jeng-Mai Chen and Malucci.