The Discipline

Hematology is the subspecialty of internal medicine that focuses on the care of patients with disorders of the blood, bone marrow, and lymphatic systems.

Clinical issues managed by hematologists include:

  • Anemias
  • Hematological malignancies and other clonal processes
  • Congenital and acquired disorders of hemostasis, coagulation, and thrombosis

Hematologists may maintain an independent practice of hematology in which patients with hematologic diseases are followed longitudinally, although a large component of hematology practice is providing consultative services for other physicians or medical institutions. Some hematologists maintain a split practice, seeing hematology and general internal medicine patients.

Hematology is most commonly coupled with training in oncology in a hematology-oncology combined fellowship program. This dual training prepares an internist to diagnose, treat, and manage a wide range of related diseases.


Hematology fellowship training requires two years of accredited training beyond completion of a general internal medicine residency, while dual certification in hematology and medical oncology requires three years of combined fellowship training. Following completion of fellowship training, trainees are eligible for board certification in hematology by the American Board of Internal Medicine.

Training Positions

In the 2021-2022 academic year, there were 2 Accreditation Council for Graduate Medical Education (ACGME)-accredited training programs in hematology with 17 trainees. There were also 180 ACGME-accredited programs in hematology and medical oncology with 1,977 trainees.

Major Professional Societies

  • American Society of Hematology

See all the career pathways open to internal medicine doctors.

Back to the July 2022 issue of ACP IMpact