A | B | C | D | E | F | G | H | I | J | K | L | M | O | P | Q | R | S | T | U | V | W | X | Y | Z

A
ABO	A system for identifying the major blood groups, depending on the presence or absence of two common antigens labeled A and B. A-type blood has the A antigen. B-type has the B antigen. AB blood has both, and O blood has neither. « Back to top
Allogeneic donation	A blood donation by a volunteer donor that is intended to be used by someone other than oneself. « Back to top
Anemia	A condition in which there is reduced oxygen delivery to the tissues due to a reduction in the oxygen-carrying capacity of circulating red cells. It may result from increased destruction of red cells, excessive blood loss or decreased production of red cells. « Back to top
Antibody	Immune system protein that can react with blood cell antigens and destroy transfused blood cells. « Back to top
Antigen	A substance that is recognized by the body as being foreign, and as such can trigger an immune response. In blood, antigens are usually, but not exclusively, found on the blood cell surface. « Back to top
Apheresis	A special blood donation procedure in which only specific blood components (plasma, platelets, red cells or white cells) are collected. Blood is drawn and processed through a cell separator, retaining the desired component and returning the rest to the body. « Back to top
Autologous donation	A donation of blood or blood components by a patient for subsequent transfusion to him- or herself. « Back to top
B
Blood group	See ABO « Back to top
Blood type	The combination of the ABO-blood groups and the positive or negative Rh-factor. See ABO and Rh factor. « Back to top
Bone marrow	Tissue that produces all blood cells in adults. The bone marrow is found inside the bones, most prominently in the pelvis, long bones and spinal cord. « Back to top
C
Cryoprecipitated AHF	Concentrated form of fibrinogen, one of the clotting proteins. « Back to top
D
Deferral	Not permitting donors to give blood, either temporarily or permanently, for medical or safety reasons. « Back to top
Derivatives	Blood products obtained from liquid or frozen plasma units that have been pooled and then chemically separated. « Back to top
Directed donation	Blood donation designated for transfusion to a specific recipient. Often comes from the friends and family of the recipient. If the intended recipient does not use the blood it may be released for use by other patients. « Back to top
F
Factor VIII	The clotting factor protein absent or decreased in patients with Hemophilia A. Also called anti-hemophilic factor. « Back to top
Fresh Frozen Plasma / FFP	Plasma frozen within 8 hours of collection. See Plasma. « Back to top
H
Hematocrit / Hct	A test measuring the percent of red cells in a sample of whole blood, used to test for anemia. « Back to top
Hemoglobin / Hgb	A protein in red blood cells containing iron, which is essential for carrying oxygen and gives the red color to healthy blood. Used to test for anemia. Blood donors must meet an established level of hemoglobin before they can donate blood. « Back to top
Hemophilia	A hereditary bleeding disorder, in which blood does not clot normally. People with the disorder bleed for longer periods of time, which is most concerning when bleeding occurs internally — in the joints, tissues, muscles, and especially the vital organs, such as the brain. Many hemophiliacs rely on regular transfusions of the clotting factor in plasma. « Back to top
Hepatitis	An inflammation of the liver. « Back to top
Hepatitis B / HBV	A virus transmitted through blood and other body fluids that causes hepatitis. All blood donations are tested for hepatitis B. Those that test positive are destroyed and the blood donor is permanently disqualified. « Back to top
Hepatitis C / HCV	A virus that causes hepatitis. All blood donations are tested for the hepatitis C virus. Blood from donors who test positive for HCV antibodies is destroyed. « Back to top
HIV / Human Immunodeficiency Virus	The virus responsible for AIDS. All blood donations are tested for HIV, and those that test positive are destroyed. Donors with confirmed positive results are permanently disqualified. « Back to top
HLA / Human Leukocyte Antigen	Any one of a number of genetic markers found on all nucleated cells of the body that determine the tissue type. Matching HLA types is important for organ transplantation. Sometimes platelet transfusions may require HLA typing as well. There are approximately 10,000 HLA types. « Back to top
I
Immune response	The reaction of the body to substances that are foreign or the body thinks are foreign. See antigen. « Back to top
L
Leukocyte	A general term for white blood cells, including granulocyte, lymphocyte, monocyte, etc. Among the functions of the leukocyte are the engulfment of bacteria, fungi and viruses. « Back to top
N
National Testing Laboratory	One of nine Red Cross centralized labs where all blood tests on blood donated to the Red Cross are performed. « Back to top
P
Plasma	The liquid portion of the blood. It contains coagulation factors and is used to treat patients who develop bleeding problems during major surgery or massive trauma. Because some of the factors lose effectiveness quickly, plasma must be frozen in order to preserve its functions. See Fresh Frozen Plasma. « Back to top
Platelets	Cellular fragments. Their primary function is to prevent bleeding. They play a part in the body's clotting mechanism. « Back to top
Pheresis	See Apheresis
Phlebotomy	The procedure in which one's vein is entered for the purpose of withdrawing blood. « Back to top
R
Red blood cells	Blood cells that carry oxygen throughout the body and give blood its red color. They are transfused to people who fail to produce their own, have severe bleeding, or a low blood count. « Back to top
Rh / Rhesus factor	A specific protein on the surface of red blood cells. The Rh factor can be "+" (present) or " -" (absent) and is usually indicated after the major blood group A, B, AB or O. 85% of people are Rh-positive « Back to top
V
vCJD / variant Creutzfeldt-Jakob Disease	The human form of 'mad cow disease' « Back to top
Venipuncture	Entering a vein for the withdrawal of blood or for intravenous medication « Back to top
W
White cells	See Leukocytes « Back to top
Whole blood	The blood in veins and arteries. Blood is made up of several elements, each of which performs a special function in the body. The transfusable parts of whole blood are red blood cells, white blood cells, plasma, and platelets. « Back to top