A doctor of internal medicine, or internist, is a specialist who treats adult and adolescent patients. An internist often serves as a primary-care physician, according to the American College of Physicians. This role requires the ability to diagnose puzzling cases and treat a wide variety of chronic and acute conditions. In addition to the education and licensing necessary for all physicians, internists receive post-doctoral training that equips them to treat the whole patient.

Qualifying for Medical School

In most cases, medical school applicants must complete a bachelor's degree before admission. Although no specific major is necessary, prospective doctors must take the required prerequisites, which typically include classes in English, math, biology, chemistry and physics.

In addition to college transcripts, medical schools require scores on the Medical College Admission Test, or MCAT, and letters of recommendation. Admission to medical programs is highly competitive, and colleges also consider the candidate's leadership ability and extracurricular activities, according to the Bureau of Labor Statistics.

Attending Medical School

Medical colleges receive their accreditation through the Liaison Committee on Medical Education, or LCME. Medical school generally takes four years, with the first two years devoted to class and lab work in subjects such as psychology, biochemistry, anatomy and medical ethics. Students also learn patient-care technique, such as how to take a medical history.

During the second two years, prospective physicians get hands-on experience treating patients in clinical settings under the supervision of experienced doctors. For example, they complete rotations in internal medicine, psychiatry, surgery, family practice and gynecology.

Completing a Residency

Medical school graduates must complete a three-year residency to qualify as specialists in internal medicine. Residents typically spend most of their time in a hospital or clinic, where they complete rotations in core areas of internal medicine, such as general medicine, coronary care and outpatient care.

Graduates also choose elective rotations in other areas of internal medicine, such as dermatology and ophthalmology, and in subspecialties of internal medicine, such as rheumatology and medical oncology.

Achieving Licensing and Certification

Before being able to practice, internists must qualify for a state license by passing the U.S. Medical Licensing Examination and fulfilling any additional requirements of the state. Alternately, physicians who've attended an osteopathic medical school take the Comprehensive Osteopathic Medical Licensing Examination.

A licensed physician who has completed a residency in internal medicine can take exams from the American Board of Internal Medicine to qualify as board-certified. Although certification is optional, it demonstrates that the internist has met high national standards of competency in internal medicine.

Opting for a Subspecialty

After residency, an internist may choose additional training to qualify in one of the many available subspecialties. Subspecialty training, called a fellowship, typically takes between one and four additional years, depending on the choice. Subspecialties include adolescent medicine, cardiovascular disease, critical care, gastroenterology, infectious diseases and hematology, among others.

Graduates of fellowship programs can qualify for additional certification in the subspecialty by passing exams from the American Board of Internal Medicine.

Physicians and Surgeons salary

• Median Annual Salary: $208,000 or more ($100/hour)