Physician Assistant (aka: Physician Associate) The physician assistant role, legally associated with a supervising physician, has allowed PAs to perform tasks previously only performed by doctors: history taking, physical examination, diagnosis, and patient management. Numerous studies have documented the ability of PAs to provide high-quality health care, comparable to that of a physician, for about 80% of the conditions seen in primary care settings. The physician assistant is prepared, both academically and clinically, to provide health care services with the direction and responsible supervision of a Doctor of Medicine (MD) or Osteopathy (DO). PA functions include performing diagnostic, therapeutic, preventive, and health maintenance services.