I just go with the classic,
Get friends from the hospital to call and leave voice mails on my friends cell phones.
"Hello? Mr. Smith, this is Eric from XXXX XXXX Hospital. It seems we over looked something on your last cell culture/ blood test. It appears that you need to make an immediate appointment with the Infectious Disease office. You can contact them at 555-555-5555."
Its a knee slapper because when they call the number back from their caller ID it connects to the hospitals operator and they are convinced its for real.
Of course, this is saved for only close family and friends.
