Hematology Terms

Agranulocytes

White blood cells that do not have visible granules in their cytoplasm. Agranulocytes include lymphocytes and monocytes.

Fibronegen

the inactive precursor of fibrin.

Azoto

nitrogen compounds

Aplastic anemia

Anemia caused by bone marrow failure resulting in deficient blood cell production, especially of red cells; pancytopenia

Delayed hypersensitivity reaction

An allergic reaction involving T cells that takes at least 12 hours to develop. Examples are various types of contact dermatitis, such as poison ivy or poison oak; the tuberculin reaction (test for TB); and rejections of transplanted tissue.

Ecchymosis

A collection of blood under the skin caused by leakage from small vessels (root chym means “juice”).

Kaposi sarcoma

Cancerous lesion of the skin and other tissues, seen most often in patients with AIDS.

Lymphoma

Any neoplastic disease of lymphoid tissue, such as Burkitt disease, Hodgkin disease, and others.

Multiple myeloma

A tumor of the blood-forming tissue in bone marrow.

Non-Hodgkin lymphoma

A widespread malignant disease of lymph nodes that involves lymphocytes. It differs from Hodgkin disease in the absence of giant Reed-Sternberg cells

Philadelphia chromosome

An abnormal chromosome found in the cells of most individuals with chronic granulocytic (myelogenous) leukemia.

Pernicious anemia

Anemia caused by failure of the stomach to produce intrinsic factor, a substance needed for the absorption of vitamin B12. This vitamin is required for the formation of erythrocytes.

Petechiae

Pinpoint, flat, purplish-red spots caused by bleeding within the skin or mucous membrane (singular, petechia).

Purpura

A condition characterized by hemorrhages into the skin, mucous membranes, internal organs, and other tissues.

Sideroplastic anemia

Anemia caused by inability to use available iron to manufacture hemoglobin. The excess iron precipitates in normoblasts (developing red blood cells).

Sjogren syndrome

An autoimmune disease involving dysfunction of the exocrine glands and affecting secretion of tears, saliva, and other body fluids. Deficiency leads to dry mouth, tooth decay, corneal damage, eye infections, and difficulty in swallowing.

Systemic lupus erythematosus

Inflammatory disease of connective tissue affecting the skin and multiple organs. Patients are sensitive to light and may show a red butterfly-shaped rash over the nose and cheeks.

Systemic sclerosis

A diffuse disease of connective tissue that may involve any system causing inflammation, degeneration, and fibrosis. Also called scleroderma because it causes thickening of the skin.

Thalassemia

A group of hereditary anemias mostly found in populations of Mediterranean descent (the name comes from the Greek word for “sea”).

Thrombocytopenia

A deficiency of thrombocytes (platelets) in the blood.

Aggluination

The clumping of cells or particles in the presence of specific antibodies.

Bilirubin

A pigment derived from the breakdown of hemoglobin. It is eliminated by the liver in bile.

Corpuscle

A small mass or body. A blood corpuscle is a blood cell.

Heparin

A substance found throughout the body that inhibits blood coagulation; an anticoagulant.

Megakarocyte

A large bone marrow cell that fragments to release platelets.

Fanconi syndrome

Congenital aplastic anemia that appears between birth and 10 years of age; may be hereditary or caused by damage before birth, as by a virus.

Hemosiderosis

A condition involving the deposition of an iron-containing pigment (hemosiderin) mainly in the liver and the spleen. The pigment comes from hemoglobin released from disintegrated red blood cells.

Idiopathic thrombocytopenic purpura (ITP)

A clotting disorder caused by destruction of platelets that usually follows a viral illness. Causes petechiae and hemorrhages into the skin and mucous membranes.

Infectious mononucleosis

An acute infectious disease caused by Epstein-Barr virus (EBV). Characterized by fever, weakness, lymphadenopathy, hepatosplenomegaly, and atypical lymphocytes (resembling monocytes)

Lymphocytosis

An increase in the number of circulating lymphocytes.

Myoelofibriosis

Condition in which bone marrow is replaced with fibrous tissue.

Neutropenia

A decrease in the number of neutrophils with increased susceptibility to infection. Causes include drugs, irradiation, and infection. May be a side effect of treatment for malignancy.

Pacytopenia

A decrease in all cells of the blood, as in aplastic anemia

Polycythemia

Any condition in which there is a relative increase in the percent of red blood cells in whole blood. May result from excessive production of red cells because of lack of oxygen, as caused by high altitudes, breathing obstruction, heart failure, or certain forms of poisoning. Apparent polycythemia results from concentration of the blood, as in dehydration.

Polycythenia vera

A condition in which overactive bone marrow produces too many red blood cells. These interfere with circulation and promote thrombosis and hemorrhage. Treated by blood removal. Also called erythremia, Vaquez-Osler disease

Septicemia

presence of microorganisms in the blood.

Spherocytic anemia

Hereditary anemia in which red blood cells are round instead of diskshaped and rupture (hemolyze) excessively.

Thrombotic thrombo-cytopenia purpura

An often-fatal disorder in which multiple clots form in blood vessels.

Von Willebrand disease

A hereditary bleeding disease caused by lack of von Willebrand factor, a substance necessary for blood clotting.