I have a copy of the International Maritime Organisation (IMO) Code of Signals on my bookshelf.
3 letter medical flag codes include:
MKH Foreskin will not go back to normal position
MKI Patient has swelling of the testicles
MLF Patient has Delirium Tremens
It's a comprehensive book to say the least!
I wonder how many times MLF has been used for a ship’s captain?
Strange there's no flag meaning "Discard all previous/following flags".
YN Cancel my last signal/message
Or in the case of medical flags...
MPR Patient has died
might do the job.
Y38.5 - medical diagnosis code indicating injury caused by terrorism involving the use of nuclear weapons.