(CNN) President Donald Trump's visit to Walter Reed on Saturday did not follow the protocol of a routine presidential medical exam, according to a person familiar with the matter.

Medical staff at Walter Reed did not get a staff-wide notice about a presidential visit to the medical center in Bethesda, Maryland, ahead of Trump's arrival, according to that source.

Typically, Walter Reed's medical staff would get a general notice about a "VIP" visit to the medical center ahead of a presidential visit, notifying them of certain closures at the facility. That did not happen this time, indicating the visit was a non-routine visit and scheduled last minute.

The source said it was possible a small group of doctors involved in Trump's medical exams were notified before Trump arrived at Walter Reed, but said all medical staff at Walter Reed would typically be aware if the President was arriving for a routine medical exam.

His two previous physical exams in office were announced ahead of time by the White House and noted on his daily public schedule, but a source with knowledge of the matter told CNN Saturday that the President's unannounced trip to the medical center was not even on the President's internal schedule as of Saturday morning.

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