a hospital recently wanted to run some test on me, I forget what for the moment, and I pointed out they'd alrready done it in 2002. They had no record of it at all (they even searched the basement where they keep the stuff written in reed pens on papyrus.)
No good complaining; if they haven't got it, they haven't got it, and I'd just as soon they didn't guess.
I keep all medical records I get, but that's hardly anything, though hospitals are more thorough in giving you copies.