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A hematologist is a physician or researcher who specializes in the study, diagnosis, and treatment of diseases of the blood and blood-forming organs, including blood cells, hemoglobin, lymph, blood-producing organs, bone marrow, and the vascular system. Physicians specializing inhematology usuallywork with the care and treatment of patients with hematological disorders, while some work in a hematology laboratory interpreting hematological testing results.


Hematology is a subspecialty of internal medicine, which in some cases overlaps with the subspecialty of oncology. Hematologists treat bleeding disorders, such as hemphilia, and hematological malignancies such as lymphoma and leukemia. They also are involved in the treatment of anemias, which are diseases associated with the lack of hemoglobin, as well as hemoglobinopathies, which are congenital abnormalities of the hemoglobin molecule or of the rate of hemoglobin synthesis.

Hematologists will be increasingly involved with the care of the elderly, for the incidence and prevalence of blood diseases and disorders increase with age. Of special concern is the prevalence of anemia in the elderly. In 2005 over 3 million people in the United States aged 65 years and older were considered to be anemic. Even if patients only have mild anemia, they still can exhibit significant functional impairment (decreased physical performance and strength) and perhaps increased mortality, especially those patients with other diseases such as congestive heart failure . Potential causes of anemia include blood loss and nutritional deficiencies, chronic illness, and inflammation, and chronic renal failure. However, about one-third of the anemias found in the elderly have no known causes. Therefore, hematologists are working with other health care professionals to better understand the causes of anemia in the elderly as well as to develop better means of screening, diagnosis and treatment of elderly patients with anemia.

The incidence of cancers associated with hematology also increases with age. For patients over the age of 60 years, treatment of non-Hodgkin lymphoma and acute myeloid leukemia is often less successful. Chronic inflammation in the elderly may stimulate the progress of non-Hodgkin lymphoma. Acute myeloid leukemia in the elderly is more resistant to chemotherapy , and recovery of bone marrow after chemotherapy is less likely.

Hematologists may also work with elderly patients who develop vascular diseases and conditions such as varicose veins , senile purpura, and leg ulcers.

Work settings

Many hematologists work directly with patients to provide care and treatment of hematological diseases. Hematologists also work in laboratories conducting and interpreting results of hematological testing. Laboratory hematologists who specialize in the diagnosis of disease are referred to as hematopathologists. Hematologists also can be associated with blood banks, where blood is procured to use in blood transfusions.


Anemia —The condition of having less than the normal number of red blood cells or less than the normal quantity of hemoglobin in the blood. The oxygen-carrying capacity of the blood is, therefore, decreased.

Blood diseases —Diseases that affect the production of blood and its components, including blood cells, hemoglobin, blood proteins, and coagulation

Hemoglobin —The substance inside red blood cells that binds to oxygen and carries it from the lungs to the tissues; responsible for the red color of blood

Leg ulcers —loss of skin on the leg or foot that takes more than 6 weeks to heal; Most leg ulcers are a symptom of diseases of the veins; other causes include arterial insufficiency, diabetes, and rheumatoid arthritis

Lymph —An almost colorless fluid that travels through vessels called lymphatics in the lymphatic system and carries cells that help fight infection and disease

Senile purpura —Easy skin bruising in older people; As people age, their skin becomes thinner and more fragile. Hence, bruises (senile purpura) tend to form easily as the blood vessels in the skin are also more fragile. The bruises are initially dark purplish red and are most common on the forearms and backs of the hands in elderly people; however, the bruising may also be due to diabetes, use of medications that interfere with blood clotting, and use of medications that can damage blood vessels.

Vascular system —A specialized network of vessels for the circulation of fluids (blood and lymph) throughout the body tissues; also referred to as the circulatory system

Varicose veins —Enlarged, twisted, painful superficial veins resulting from poorly functioning valves; In normal veins, valves in the vein keep blood moving forward toward the heart; With varicose veins, the valves do not function properly, allowing blood to remain in the vein; Pooling of blood in a vein causes it to enlarge; Common in the elderly

Care team role

The hematologist works with other caregivers (for example, oncologists, transplant physicians, nutritionists, pharmacists, social workers, registered nurses and nurse practitioners, physician assistants, palliative care and end-of-life (Hospice) specialists) to treat patients with blood diseases. They may perform or be involved in activities such as bone marrow aspiration, bone marrow biopsy , blood transfusions, prescription of medications and other aids such as pressure stockings, diet and vitamins/minerals planning, chemotherapy, and autologous or allogenic stem cell transplants.


To become a hematologist, a person must first obtain training as a physician at an accredited medical school before obtaining advanced training in hematology. After completion of medical school, the doctor must participate in a two to four year residency program in internal medicine, followed by advanced training in hematology, which includes a hospital residency with course work and hands-on training in the treatment of blood disorders. Hematologists must be board certified by the American Board of Internal Medicine. After completion of a hematologist residency program, the physician is eligible for the hematology certification examination by the American Board of Internal Medicine. In addition to required continued education courses that all physicians must take, a hematologist must participate in the Maintenance of Certification Program for hematologists, which must be completed every ten years.



Balducci, Lodovico, Erschler, William, and de Gaetano, Giovanni (eds.) Blood Disorders in the Elderly. Cambridge, UK: Cambridge University Press, 2007.


American Society of Hematology, 1900M Street, NW, Suite 200, Washington, DC, 20036, 202-776-0544, 202-776 0545, [email protected], http://www.hematology.org.

International Society for Laboratory Hematology, 5 Revere Drive, Suite 200, Northbrook, IL, 20036, 312-238 0900, [email protected], http://www.islh.org.

International Society of Hematology, http://www.ishworld.org.

Judith L. Sims