My manager is great!
I had to tell him I'll learn next week if it's time to start the transplant evaluation process. He said he won't put me on any high-impact projects so I won't need to worry about dropping everything when I get the call, but that he'll make sure he keeps giving me projects that I find interesting. That sounds perfect! I'll still have good things to work on, but it'll all be lower stress for me.
I also talked to my team lead last week and he was very understanding, too. We agreed that I'll come up with a daily status sheet that I'll keep posted someplace so he (or someone else) will be able to pick up where I leave off and I'll make sure I check in all files every day. Normally, we leave files checked out until we're done with them (several days at a time). My manager mentioned today that the two of them talked & I should just let them know of any limitations & not to worry on their account.