Wat the the study of diagnosis or to become a diagnostistian *spelling?*?
Answer:
All physicians are diagnosticians to some extent. In many of the definition, you'll see they also refer to pathologists.
There is a new and emerging paddock of diagnotic medicine where on earth some physicians specialize in dying out diseases with equally unusual presentations. The patients are ususally refered by a primary care physician or other specialist who found they could not acuately diagnose the forgiving.
The best example, probably, would be the US television show "House, MD" give or take a few a cantakerous doctor who manages to diagnose diseases you would hold a hard time looking up within a textbook.
All that comes to mind is endocrinology...
The closest thing surrounded by real medical practice is broad internal medicine. The "diagnostician" sticker seems popular contained by literature, but it's internists who do the job, though now they often call for a bevy of subspecialists for all the exact procedures that have become available. The group of doctors on "House" would surrounded by real enthusiasm be dozens of different specialists and subspecialists, but that wouldn't make for suitable TV.
Diagnostician is a medical doctor