Hematology - the subspecialty of Internal Medicine involving the diagnosis and treatment of blood disorders. While an internist or family doctor treats many types of abnormalities, consultation with a hematologist is obtained in special or difficult cases. A hematologist evaluates and treats patients with anemia, bleeding disorders, or leukemia.

Medical Oncology - the subspecialty of Internal Medicine involving the diagnosis and treatment of malignancy (cancer). The medical oncologist does not perform surgery but assists with preoperative evaluation, staging (determination of the extent of spread of a cancer), and treatment planning for cancer patients. An oncologist's skills are necessary in cases requiring special knowledge in diagnosis and treatment of cancer. If chemotherapy (drug treatment for cancer) is needed, it is administered by the oncologist.