From the NFLPA:
The following information is needed in order for a player to be granted a Therapeutic Use Exemption (TUE) for the use of a stimulant to treat ADD in the NFL (this includes players at the Combine).
Letter from prescribing physician which includes:
Criteria for diagnosis
Reports of testing used to make diagnosis
They must have all of these elements to be granted a TUE. They don't have to bring it to the Combine but the sooner that they send all of this information to Dr. Brown and Dr. Lombardo, this will be taken care of.