CMAs, or certified medical assistants, perform a variety of clinical and administrative support tasks for physicians and other supervising staff. You find CMAs in doctors' offices, hospitals, clinics, and other healthcare facilities. As a CMA, you may be responsible for clerical or administrative tasks, or you may have clinical job duties. Your specific tasks vary, depending on the facility. General responsibilities may include preparing exam rooms, collecting lab specimens, interviewing patients, providing medication or vaccinations, and assisting the doctor during exams. When not working directly with patients, you may answer phone calls, arrange referrals and hospital stays, and restock medical supplies. CMAs perform many of the same tasks as non-certified medical assistants, but their certification shows a level of mastery for the job.