Glossary
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ABO Blood Group
The major human blood group system. The ABO type of a person depends upon the presence or absence of two genes, A and B. These genes determine the configuration of the red blood cell surface. A person can be A, B, AB, or O. If a person has two A genes, their red blood cells are type A. If a person has two B genes, their red cells are type B. If the person has one A and one B gene, their red cells are type AB. If the person has neither the A nor B gene, they are type O.
ALYX
ALYX is an automated system that allows donors to give enough red blood cells to make two units. ALYX collects only the red blood cells, and returns the other components of the blood back to the donor. To qualify as an ALYX donor, males must be 5'1" and weigh at least 130 pounds. Potential female donors must be 5'5" and weigh at least 150 pounds. A typical ALYX donation lasts 20-25 minutes - a little longer than a whole blood donation. ALYX donors can donate once every four months, and the ALYX needle is smaller than the one used for a whole blood donation.
Anemia
The condition of having less than the normal number of red blood cells or less than the nomal quantity of hemoglobin in the blood. The oxygen-carrying capacity of the blood is, therefore, decreased. Persons with anemia may feel tired and fatigue easily, appear pale, develop palpitations and become unusually short of breath.
Antibody
An immunoglobulin, a specialized immune protein, produced because of the introduction of an antigen into the body, and which possesses the remarkable ability to combine with the very antigen that triggered its production. The production of antibodies is a major function of the immune system and is carried out by a type of white blood cell called a B cell (B lymphocyte). Antibodies can be triggered by and directed at foreign proteins, microorganisms, or toxins.
Antigen
A substance that is capable of causing the production of an antibody. Antigens may or may not lead to an allergic reaction.
Apheresis (hemapheresis, pheresis)
The process of removing a specific component from blood and returning the remaining components to the donor, in order to collect more of one particular part of the blood than could be separated from a unit of whole blood.
Aplastic anemia
Anemia due to failure of the bone marrow to produce blood cells, including red and white blood cells as well as platelets.
Artery
A vessel that carries blood that is high in oxygen content away from the heart to the farthest reaches of the body. Since blood in arteries is usually full of oxygen, the hemoglobin in the red blood cells is oxygenated. The resultant form of hemoglobin (oxyhemoglobin) is what makes arterial blood look bright red.
Autologous
In blood transfusion and transplantation, a situation in which the donor and recipient are the same person. Patients scheduled for non-emergency surgery may be autologous donors by donating blood for themselves that will be stored until the surgery.
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Blood
The fluid in the body that contains red and white cells as well as platelets, proteins, plasma and other elements. It is transported throughout the body by the circulatory system.
Blood Bank
A place where blood is collected from donors, typed, separated into components, stored, and prepared for transfusion to recipients. A blood bank may be a separate free-standing facility or part of a larger laboratory in a hospital.
Blood Group
An inherited feature on the surface of the red blood cells. A series of related blood types constitute a blood group system such as the Rh or the ABO system.
Blood Pressure
The pressure of the blood within the arteries. It is produced primarily by the contraction of the heart muscle. It's measurement is recorded by two numbers. The first (systolic pressure) is measured after the heart contracts and is highest. The second (diastolic pressure) is measured before the heart contracts and lowest. Elevation of blood pressure is called "hypertension."
Blood Transfusion
The transfer of blood or blood products from one person (the donor) into another person (the recipient's) bloodstream.
Bone Marrow
The soft substance that fills bone cavities. It is composed of mature and immature blood cells and fat. The bone marrow is a highly cellular blood-forming tissue filling the cavities of bones. The blood cells formed in the bone marrow include white blood cells, red blood cells and platelets. Diseases or drugs that affect the bone marrow can affect the "total counts" of these cells.
Bone Marrow Transplant (BMT)
A procedure in which doctors replace bone marrow that is diseased (or damaged) with healthy bone marrow. The bone marrow to be replaced may be deliberately destroyed by high doses of chemotherapy and/or radiation therapy. The replacement marrow may come from another person, or it may be the patient’s own marrow (which was removed and stored before treatment). When marrow from an unrelated donor is used, the procedure is an allogeneic bone marrow Autologous bone marrow transplantation uses the patient’s own marrow.
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Capillary
One of the tiny blood vessels that connect the arterioles (the smallest divisions of the arteries) and the venules (the smallest divisions of the veins). The capillaries form a fine network in many parts of the body. The walls of the capillaries act as semipermeable membranes permitting the exchange of various substances between the blood stream and the tissues of the body. The substances that are interchanged through the capillary walls include fluids and the key gases oxygen and carbon dioxide.
Chemotherapy
Drug therapy for cancer. Also called "chemo" for short. Chemotherapy is usually systemic treatment, meaning that the drugs flow through the bloodstream to nearly every part of the body.
Cytomegalovirus (CMV)
A virus that infects 50-85% of adults in the US by age 40 and is also the virus most frequently transmitted to a child before birth. Persons with symptoms have a mononucleosis-like syndrome with prolonged fever and mild hepatitis. Once a person becomes infected, the virus remains alive and usually dormant within that person's body for life. Recurrent disease rarely occurs unless the person's immune system is suppressed due to therapeutic drugs or disease.
Cytoplasm
All of the substance of a cell outside of the nucleus. The cytoplasm contains a number of different types organelles such as the mitochondria. Most, but not all, cells have cytoplasm
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DNA (Deoxyribonucleic acid)
One of two types of molecules that encode genetic information. (The other is RNA. In humans DNA is the genetic material; RNA is transcribed from it. In some other organisms, RNA is the genetic material and, in reverse fashion, the DNA is transcribed from it.) DNA is a double-stranded molecule held together by weak hydrogen bonds between base pairs of nucleotides. The molecule forms a double helix in which two strands of DNA spiral about one other. The double helix looks something like an immensely long ladder twisted into a helix, or coil. The sides of the "ladder" are formed by a backbone of sugar and phosphate molecules, and the "rungs" consist of nucleotide bases joined weakly in the middle by the hydrogen bonds.
Donor
The giver of a tissue or organ, for example, of blood or a kidney.
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Erythrocyte
Cells that carry oxygen to all parts of the body. Also called red blood cells (RBCs).
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Food and Drug Administration (FDA)
The FDA is the Food and Drug Administration, an agency within the U.S. Public Health Service, which is a part of the Department of Health and Human Services. FDA investigators examine blood bank operations, from record-keeping to testing for contaminants.
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Genetic
Having to do with genes, structures found in every cell of the body. Each gene contains information that directs the activities of cells and controls the way an individual develops.
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Hemapheresis (apheresis, pheresis)
The process of removing a specific component from blood and returning the remaining components to the donor, in order to collect more of one particular part of the blood than could be separated from a unit of whole blood.
Hematologist
A doctor who specializes in treating diseases of the blood.
Hemoglobin
The oxygen-carrying pigment and predominant protein in the red blood cells. Hemoglobin forms an unstable, reversible bond with oxygen. In its oxygenated state it is called oxyhemoglobin and is bright red. In the reduced state it is called deoxyhemoglobin and is purple-blue.
Hepatitis
Inflammation of the liver.
Hepatitis B (HBV)
Inflammation of the liver due to the hepatitis B virus (HBV). Symptoms include fatigue, jaundice, nausea, vomiting, dark urine, light stools. Diagnosis is by blood test. Treatment is via anti-viral drugs and/or hepatitis B immunoglobulin (HBIG).
Hepatitis C (HCV)
Inflammation of the liver due to the hepatitis C virus (HCV). HCV causes most transfusion-associated hepatitis, and the damage it does to the liver can lead to cirrhosis and cancer. At least half of HCV patients develop chronic hepatitis C infection. Diagnosis is by blood test. Treatment is via anti-viral drugs. Chronic hepatitis C may be treated with interferon, sometimes in combination with anti-virals. There is no vaccine for hepatitis C.
Hereditary
Genetic transmission from parent to child.
Histocompatible
The prefix histo- means tissue. The term histocompatible is literally tissue compatible. If a donor and recipient are histocompatible (like identical twins), a transplant will be easily accepted.
Hodgkin's Disease (Hodgkin Lymphoma)
A malignant disease of the lymph nodes (lymphoma) that occurs most often in patients who are in their 20s or 30s. It can spread through the body, probably via the lymphatic ducts. Symptoms include enlarged lymph nodes, weight loss, night sweats, and itching. Treatment is via radiation and/or chemotherapy. Hodgkin’s disease is life-threatening if untreated, but has a very high cure rate.
Human Leukocyte Antigens (HLA)
The major human histocompatibility system. HLA-typing is done before transplantation to determine the degree of histocompatibility.
Human Immunodeficiency Virus (HIV)
Human Immunodeficiency Virus, the cause of AIDS (acquired immunodeficiency syndrome). HIV has also been called the human lymphotropic virus type III, the lymphadenopathy-associated virus and the lymphadenopathy virus. It is a retrovirus. (A retrovirus has an RNA genome and a reverse transcriptase enzyme. Using the reverse transcriptase, the virus uses its RNA as a template for making complementary DNA which can integrate into the DNA of the host organism).
Hypertension
High blood pressure, defined as a repeatedly elevated blood pressure exceeding 140 over 90 mmHg -- a systolic pressure above 140 with a diastolic pressure above 90. It can cause blood vessel changes in the back of the eye (retina), abnormal thickening of the heart muscle, kidney failure, and brain damage. For diagnosis, there is no substitute for measurement of blood pressure. No specific cause for hypertension is found in 95% of cases. Hypertension is treated with regular aerobic exercise, weight reduction (if overweight), salt restriction, and medications.
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Immune System
A complex system that is responsible for distinguishing us from everything foreign to us, and for protecting us against infections and foreign substances. The immune system works to seek and kill invaders.
Immunology
The study of all aspects of the immune system including its structure and function, disorders of the immune system, blood banking, immunization and organ transplantation.
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Leukemia
Cancer of the blood cells. The growth and development of the blood cells are abnormal. Strictly speaking, leukemia should refer only to cancer of the white blood cells (the leukocytes) but in practice it can apply to malignancy of any cellular element in the blood or bone marrow, as in red cell leukemia (erythroleukemia). Leukemia is a type of cancer. Cancer is a group of more than 100 diseases that have two important things in common. One is that certain cells in the body become abnormal. Another is that the body keeps producing large numbers of these abnormal cells. Each year, nearly 27,000 adults and more than 2,000 children in the United States learn that they have leukemia.
Leukocyte
Cells that help the body fight infections and other diseases. Also called white blood cells (WBCs).
Lymphocyte
A small white blood cell (leukocyte) that plays a large role in defending the body against disease. Lymphocytes are responsible for immune responses. There are two main types of lymphocytes: B cells and T cells. The B cells make antibodies that attack bacteria and toxins while the T cells attack body cells themselves when they have been taken over by viruses or have become cancerous. Lymphocytes secrete products (lymphokines) that modulate the functional activities of many other types of cells and are often present at sites of chronic inflammation.
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Malignant
Resistant to treatment or severe, as in malignant hypertension. When referring to an abnormal growth, it implies a tendency to spread to other organs or areas of the body (metastasize), and implies the presence of cancer.
Marrow
The soft substance that fills bone cavities. It is composed of mature and immature blood cells and fat. The bone marrow is a highly cellular blood-forming tissue filling the cavities of bones. The blood cells formed in the bone marrow include white blood cells, red blood cells and platelets. Diseases or drugs that affect the bone marrow can affect the "total counts" of these cells.
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National Institutes of Health (NIH)
The National Institutes of Health (NIH) is an important U.S. health agency. It is devoted to medical research. Administratively under the Department of Health and Human Services (HHS), the NIH consists of 20-some separate Institutes and Centers.
Nucleus
In cell biology, the structure that houses the chromosomes.
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Oncology
The field of medicine devoted to cancer. Literally, oncology means the study of tumors.
Osteoporosis
Thinning of the bones with reduction in bone mass due to depletion of calcium and bone protein. Osteoporosis predisposes a person to fractures, which are often slow to heal and heal poorly. It is more common in older adults, particularly post-menopausal women; in patients on steroids; and in those who take steroidal drugs.
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Pheresis (hemapheresis, apheresis)
The process of removing a specific component from blood and returning the remaining components to the donor, in order to collect more of one particular part of the blood than could be separated from a unit of whole blood.
Phlebotomist
A person who draws blood.
Phlebotomy
Obtaining blood from a vein.
Plasma
The liquid part of the blood and lymphatic fluid, which makes up about half of its volume. Plasma is devoid of cells and, unlike serum, has not clotted. Blood plasma contains antibodies and other proteins. It is taken from donors and made into medications for a variety of blood-related conditions.
Plasma Donation
The procedure is done in a walk-in facility, where whole blood is taken through an IV needle, and separated into plasma and blood cells. The blood cells are then returned intravenously to the donor.
Platelet
An irregular, disc-shaped element in the blood that assists in blood clotting. During normal blood clotting, the platelets clump together (aggregate). Although platelets are often classed as blood cells, they are actually fragments of large bone marrow cells called megakaryocytes.
Platelet Count
The calculated number of platelets in a volume of blood, usually expressed as platelets per cubic millimeter (cmm) of whole blood. Platelets are the smallest cell-like structures in the blood and are important for blood clotting and plugging damaged blood vessels. Platelet counts are usually done by laboratory machines that also count other blood elements such as the white and red cells. They can also be counted by use of a microscope. Normal platelet counts are in the range of 150,000 to 400,000 per microliter (or 150 - 400 x 109 per liter).
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Radiation Therapy
The use of high-energy rays to damage cancer cells, stopping them from growing and dividing. Like surgery, radiation therapy is a local treatment that affects cancer cells only in the treated area.
Red Blood Cell (RBC)
One of the blood cells that carry oxygen. Red cells contain hemoglobin and it is the hemoglobin which permits them to transport oxygen (and carbon dioxide). Hemoglobin, aside from being a transport molecule, is a pigment. It gives the cell its red color (and name). A red blood cell is sometimes simply referred to as a red cell. It is also called an erythrocyte.
Red Blood Count
The number of red blood cells (RBCs) in a volume of blood. The normal range varies slightly between laboratories but is generally between 4.2 - 5.9 million cells/cmm. This can also be referred to as the erythrocyte count and can be expressed in international units as 4.2 - 5.9 x 1012 cells per liter.
Rh Factor
An antigen found in the red blood cells of most people: those who have Rh factor are said to be Rh positive (Rh+), while those who do not are Rh negative (Rh-). Blood used in transfusions much match donors for Rh status as well as for ABO blood group, as Rh- patients will develop anemia if given R+ blood. Rh stands for rhesus monkeys, in whose blood this antigen was first found.
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Sickle Cell Anemia
A genetic blood disease due to the presence of an abnormal form of hemoglobin, namely hemoglobin S. Hemoglobin is the molecule in red blood cells that transports oxygen from the lungs to the fartherest reachs of the body. Sickle cell anemia affects millions of people throughout the world. In the USA, sickle cell disease occurs in about 1 in every 500 African-American births and 1 in every 1,000-1,400 Hispanic-American births. Sickle cell anemia is caused by an error in a gene that makes the beta globin chain of hemoglobin. The resultant abnormal hemoglobin (sickle hemoglobin) deforms the red blood cells when they are under low oxygen conditions. Children who inherit 2 copies of the sickle gene, one from each parent, have sickle cell anemia. Children who inherit the sickle gene from only one parent do not have the disease, but will carry the sickle cell trait. Individuals with sickle cell trait generally have no symptoms. About 2 million Americans (or 1 in 12 African-Americans) carry the sickle gene.
Stem Cells
One of the human body's master cells, with the ability to grow into any one of the body's more than 200 cell types. All stem cells are unspecialized (undifferentiated) cells that are characteristically of the same family type (lineage). They retain the ability to divide throughout life and give rise to cells that can become highly specialized and take the place of cells that die or are lost. Stem cells contribute to the body's ability to renew and repair its tissues. Unlike mature cells, which are permanently committed to their fate, stem cells can both renew themselves as well as create new cells of whatever tissue they belong to (and other tissues). Bone marrow stem cells, for example, are the most primitive cells in the marrow. From them all the various types of blood cells are descended. Bone marrow stem-cell transfusions (or transplants) were originally given to replace various types of blood cells.
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T Lymphocytes (T-Cell)
A type of white blood cell that is of crucial importance to the immune system. Immature T cells (termed T-stem cells) migrate to the thymus gland in the neck, where they mature and differentiate into various types of mature T cells and become active in the immune system in response to a hormone called thymosin and other factors. T-cells that are potentially activated against the body’s own tissues are normally killed or changed during this maturation process.
Transfusion
The transfer of blood or blood products from one person (the donor) into another person (the recipient's) bloodstream. In most situations, this is done as a lifesaving maneuver to replace blood cells or blood products lost through severe bleeding. Transfusion of your own blood (autologous) is the safest method but requires planning ahead and not all patients are eligible. Directed donor blood allows the patient to receive blood from known donors. Volunteer donor blood is usually most readily available and, when properly tested has a low incidence of adverse events.
Transplant
The grafting of a tissue from one place to another, just as in botany a bud from one plant might be grafted onto the stem of another. The transplanting of tissue can be from one part of the patient to another (autologous transplantation), as in the case of a skin graft using the patient’s own skin; or from one patient to another (allogenic transplantation), as in the case of transplanting a donor kidney into a recipient.
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Universal Blood Donor
An individual with type O negative blood. Patients of any blood type can receive type O blood.
Universal Blood Recipient
An individual with type AB blood. Patients of type AB blood type can receive all blood types.
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Veins
A blood vessel that carries blood low in oxygen content from the body back to the heart. The deoxygenated form of hemoglobin (deoxyhemoglobin) in venous blood makes it appear dark. Veins are part of the afferent wing of the circulatory system which returns blood to the heart.
Volunteer Donor
An individual that willingly and without compensation donates blood, blood components or bodily tissue.
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White Blood Cell (WBC)
One of the cells the body makes to help fight infections. There are several types of white blood cells (leukocytes). The two most common types are the lymphocytes and neutrophils (also called polymorphonuclear leukocytes, PMNs, or "polys"). Lymphocytes are made in lymphoid tissue in the spleen, lymph nodes, and thymus gland. There are different kinds of lymphocytes. Lymphocytes identify foreign substances from germs (bacteria or viruses) in the body and produce antibodies and cells that specifically target them. It takes from several days to weeks for lymphocytes to recognize and attack a new foreign substance. Neutrophils are also major players in the body's defense against bacterial infections. Neutrophils are made in the bone marrow and circulate in the bloodstream. Neutrophils move out of the blood vessels into the infected tissue to attack the bacteria.
White Blood Cell Count
The number of white blood cells in the blood. The normal range for the white blood cell count varies between laboratories but is usually between 4,300 and 10,800 cells per cubic millimeter. This can also be referred to as the leukocyte count and can be expressed in international units as 4.3 - 10.8 x 109 cells per liter. A low white blood cell count is called leukopenia. A high white blood cell count is termed leukocytosis.
Whole Blood
Blood is made up of several elements, each of which performs a special function in the body. These elements are red blood cells, white blood cells, plasma, cryoprecipitate and platelets. Blood is collected as whole blood.
* definitions from MedTerms.com