Hematology Terms
Agranulocyte: A leukocyte without definite cytoplasmic granules.
Agranulocytosis: Complete or nearly complete absence of the granular leukocytes from the blood and bone marrow.
Aleukemic Leukemia: A fatal condition of the blood-forming tissues, characterized by marked proliferation of immature cells in the bone marrow, without their presence, in any great numbers, in the blood steam.
Anemia: A condition in which the blood is deficient in quantity or quality of erythrocytes.
Anisocytosis: Variation in size of the erythrocytes.
Anomaly: Abnormality.
Anoxemia: Lack of normal proportion of oxygen in the blood.
Antecubital Space: The area on the forearm frontal to the elbow.
Anticoagulant: A substance that prevents the coagulation of blood. Commonly used ones are potassium oxalate, sodium oxalate, sodium citrate, EDTA and heparin.
Aplasia: Incomplete or defective blood development; cessation of blood cell formation.
Aplastic Anemia: Anemia characterized b incomplete or effective blood development.
Asynchronous: Uncoordinated development as in abnormal cell development.
Azurophilic Granule: Rounded, discrete, reddish-purple granule, smaller than the granules of neutrophils; 1-10 are common in lymphocytes, and they are very numerous, and smaller, in the cytoplasm of monocytes
Band Form: In the Schilling classification, a neutrophil with the nucleus unsegmented and ribbonlike; also stab, staff, nonfilamented.
Basket Cell: A degenerated primitive cell which has ruptured and in which the cell nucleus appears as a pale staining smear without prescribed form or shape.
Basopenia: An abnormal decrease in the number of basophils.
Basophil: A granular leukocyte, the granules of which have affinities for the basic dye of Wright stain (methylene blue). The granules are large, irregular and blue-black in color.
Basophilia: An abnormal increase in the number of basophils.
Basophilic: Staining readily with basic dyes, for example, blue with Ramanovsky type stains.
Binary Fission: Simple cell division.
Bleeding Time: The time required for a small standardized wound, made in the capillary bed of the finger or ear lobe, to stop bleeding.
Blood Dyscrasia: A disease of the blood or blood-forming organs.
Buffy Coat: The layer of leukocytes that collects immediately above the erythrocytes in sedimented or centrifuged whole blood.
Cabot’s Rings: Lines in the form of loops or figures-of-eight seen in erythrocytes in severe anemias.
Centriole: A minute cell organoid within the centrosome.
Centrosome: An area of condensed cytoplasm active in mitosis.
Chemotaxis: the phenomenon of movement of leukocytes caused by a chemical influence.
Chromatin: The more stainable portion of the cell nucleus contains genetic materials.
Clot Retraction: The rate and degree of contraction of the blood clot.
Coagulation Time: The time required for venous blood, in the absence of all tissue factors, to clot in glass tubes under controlled conditions.
Cocatalyst: A substance that works in tandem with another group of chemicals to accelerate a reaction velocity without being used up in the reaction.
Color Index: The ratio between the amount of hemoglobin and the number of red blood cells.
Complete Blood Count: A hematology study which consists of a red cell count, white cell count, hematocrit, hemoglobin, and blood smear study including differential white cell count.
Congenital: Born with a person; existing at or before birth.
Cooley’s Anemia (Mediterranean Disease or Thalassemia): A chronic progressive anemia commencing early in life and characterized by many normoblasts in the blood, unusual facies, splenomegaly and familial and racial incidence. Target type red blood cells are often present in the peripheral blood.
Crenation: The scalloped or notched appearance of the periphery of erythrocytes found when the cells are suspended in a hypertonic solution. Also found in smears, caused by dirty glassware, slow drying, and poor smearing technique.
Cytoplasm: Protoplasm of a cell excluding the nucleus.
DNA: Deoxyribonucletic acid.
Differential Count: An en1.meration of the types of white blood cells seen on a stained blood smear.
Discrete: Separate.
Dyscrasia: Abnormality.
Ecchymosis: Subcutaneous extravastion of blood covering a large area.
Endothelial Leukocyte: Monocyte.
Eosinopenia: An abnormal decrease in eosinophils.
Eosinophil: A granular leukocyte, the granules of which have an affinity for the acid dye of Wright’s stain (eosin). The granules are large, round, uniform in size, red-orange in color and are shiny and refractile.
Eosinophilia: A relative or absolute leukocytosis in which the main increase is in eosinophils.
Eosinophilic: Readily stained with eaosin, red-orange stain.
Epigastric: Pertaining to the upper middle portion of the abdomen.
Erythremia: A disease marked by persistent polycythemia and increased blood volume also polychythemia vera.
Erythrocyte: Red blood cell.
Erythrocytosis: An increase in the total number of erythrocytes.
Erythrogenic: Producing erythrocytes.
Erythroleukemia: An abnormal condition characterized by proliferation of erythroblastic and myeloblastic cells.
Erythropenia: A decrease in the number of red cells in the blood.
Erythropoiesis: The production of erythrocytes.
Etiology: The theory of the causation of a disease.
Extravascular: Occurring outside the blood vessels.
Extrinsic: Originating outside of the particular area.
Fibril: A microscopic filament often composed of fibrin.
Fibrin: The end product of the clotting mechanism that forms a network of fibers that enmesh the formed elements of blood.
Fibrinogen: The precursor of fibrin that is present normally in the plasma and produced by the liver.
Fragility Test (Osmotic): A test devised to measure the resistance of the erythrocytes to break down (hemolyze) when subjected to varying concentrations of hypotonic salt solutions.
Fulminating: Sudden and severe.
Golgi Apparatus: A meshwork of lipid containing fibrils within the cytoplasmic portion of a cell.
Granulocyte: A white blood cell that contains specific cytoplasmic granules (neutrophils, eosinophils, and basophils); these granules are peroxidase positive.
Granulocytosis: The presence of increased numbers of granulocytes in the blood.
Granulocytopenia (Granulopenia): A decrease in the number of granulocytes in the blood.
Granulopoiesis: The production of granulocytes.