Adamu the first appointed Minister of Education by President Buhari, is reportedly in a hospital in Berlin, Germany.
He would be flown abroad in recent months, Sahara Reporters says the latest trip was the third time.
The minister is reportedly undergoing treatment for a kidney related procedure.
However, the reason for the current trip is still unknown.
There are concerns that his absence has affected issues including reopening of schools. The University of Lagos (UNILAG) leadership imbroglio, among others.
Adamu is expected back in the country soon, He has not been seen in public in recent weeks.
Born May 25, 1956, Adamu is a long time ally of President Muhammadu Buhari.
Prior to his appointment as Minister in 2015, the Bauchi indigene was the Secretary of Buhari’s Presidential Transition Committee.