People who feel ill commonly pick up the phone and make an appointment with their primary care physician, internal medicine practitioner or family practice doctor. These specialties attract doctors who are somewhat of a jack-of-all-trades. It is their job to make an initial diagnosis, prescribe medicine for common illnesses, and make referrals to specialists. Patients often feel close to their family physician and trust him or her to correctly determine the source of any medical problems. However, according to a physician at Baltimore’s Johns Hopkins School of Medicine, every year at least 150,000 people in the United States suffer harm from medical errors due to their doctor’s missed or incorrect diagnosis.