Hematologic and Immunologic Terms

Hematology

The study of blood, blood-forming tissues, and blood disorders

RBC

Red blood cells that transport oxygen and carbon dioxide in the blood

WBC

White blood cells that help protect the body against infection and disease

Thrombocytes

Blood cells involved in clot formation; also called platelets

PCV

Packed cell volume; the percentage of blood volume occupied by red blood cells

Hgb

Hemoglobin; the protein in red blood cells that carries oxygen

Normocytic

Red blood cells that are normal in size

Macrocytic

Red blood cells that are larger than normal

Microcytic

Red blood cells that are smaller than normal

Anisocytosis

Variation in the size of red blood cells

Normochromic

Red blood cells with a normal amount and concentration of hemoglobin

Polychromic

Red blood cells that stain bluish due to increased numbers of immature red blood cells

Hypochromic

Red blood cells with less hemoglobin that normal, appearing paler than normal

Polycythemia

An abnormally increased number or concentration of red blood cells

Anemia

A decrease in red blood cells, hemoglobin, or both, resulting in reduced oxygen-carrying capacity

Hemorrhage

Excessive or abnormal loss of blood from blood vessels

Hemolysis

Destruction or rupture of red blood cells, releasing hemoglobin

Hypoplasia

Incomplete or underdevelopment of a tissue or organ due to reduced cell production

Aplasia

Failure of a tissue or organ to develop or failure of its cells to be produced

Jaundice

Yellow discoloration of the skin, mucous membranes, or tissues caused by increased bilirubin

Icterus

The medical term for yellow discoloration caused by increased bilirubin

Acute

A disease or condition that develops rapidly and is usually short in duration

Chronic

A disease or condition that develops slowly or persists for a long period

Spherocyte

A red blood cell that is abnormally spherical due to loss of part of its cell membrane

Platelets

Small cell fragments that help form blood clots and stop bleeding

Thrombocytosis

An abnormally high number of platelets in the blood

Thrombocytopenia

An abnormally low number of platelets in the blood

Petechiation

The presence of small, pinpoint areas of bleeding under the skin or mucous membranes

Ecchymosis

A larger area of bleeding under the skin, commonly appearing as a bruise

Melena

Black, tarry feces caused by digested blood, usually from bleeding in the upper gastrointestinal tract

Microhematocrit

A laboratory test that measures the packed cell volume of blood using a small capillary tube

Regenerative Anemia

Anemia in which the bone marrow responds by producing and releasing increased numbers of immature red blood cells

Hemoglobinemia

An abnormally high concentration of free hemoglobin in the blood, usually caused by intravascular hemolysis

Hemoglobinuria

The presence of free hemoglobin in the urine, usually caused by intravascular hemolysis

Hyperbilirubinemia

An abnormally high concentration of bilirubin in the blood

Coombs Test

A test used to detect antibodies or complement attached to red blood cells, often used to investigate immune-mediated hemolytic anemia

Rhipicephalus sanguineus

The brown dog tick, an important tick that can transmit Ehrlichia canis