Named in the medical ledger (6)
I believe the answer is:
called
'named' is the definition.
('called' can be a synonym of 'named')
'in the medical ledger' is the wordplay.
'in' says the answer is hidden in the clue.
'CALLED' is hidden in the letters of 'medical ledger'.
(Other definitions for called that I've seen before include "Came to visit" , "Assigned a name to" , "Named" , "Having a specified name" , "Phoned or visited" .)