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This glossary of commonly used organ donation, transplantation and dialysis access terms is courtesy of OrganDonor.Gov, with adaptation by the Transplant Center at Beth Israel Deaconess Medical Center, Boston, Massachusetts.

The official U.S. Government web site for organ and tissue donation and transplantation,, is maintained by the Health Resources and Services Administration (HRSA), Healthcare Systems Bureau (HSB), Division of Transplantation, an agency of the U.S. Department of Health and Human Services (HRSA).

Portions of the glossary were also adapted from and courtesy of, HRSA's 2004 Partnering With Your Transplant Team: The Patient's Guide to Transplantation. Rockville, MD: Health Resources and Services Administration, Special Programs Bureau, Division of Transplantation.

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ABO (Blood Type) Incompatible
Refers to a transplant donor and recipient whose blood type does not match. ABO is a blood type classification system. There are four main blood types - A, B, AB and O - determined by the presence of certain proteins on the surface of red blood cells. When blood types do not match, donor tissue and organs can be rejected by the recipient's immune system. In some cases, however, using plasmapharesis and immunosuppressive drugs, it is possible to transplant organs even when donors and recipients have different blood types. See plasmapharesis and immunosuppressive drugs.

The system of ensuring that organs and tissues are distributed fairly to patients who are in need.

An abnormal swelling that can occur along the path of an arteriovenous graft or fistula. If it reaches a size that is 2.5 times greater than the graft or fistula, surgical repair is recommended to prevent rupture.

A protein substance made by the body's immune system to attack a foreign substance, for example, a transplanted organ, blood transfusion, virus or pregnancy. Because antibodies attack transplanted organs, transplant patients must take powerful drugs. (See anti-rejection medicine.)

A foreign substance, such as is on a transplanted organ or tissue, which triggers the body to reject or destroy it.

Anti-Rejection Medicine (immunosuppressive drugs)
Medicines that reduce the body's ability to reject a transplanted organ or tissue.

The largest artery in the body. This is the main conduit of blood as it leaves the heart carrying oxygen and nutrients. All arteries branch from this main trunk.

A thick-walled blood vessel that carries oxygenated blood from the heart to the tissues of the body.

A buildup of fluid in the abdomen usually associated with liver disease.

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A tiny piece of tissue removed from the body (usually with a needle) and examined under a microscope. This test is performed to diagnose rejection of a transplanted organ.

A muscular pouch that stores urine until it is passed from the body.

Blood Vessels
The arteries, veins, and capillaries through which blood circulates.

Brain Death
Occurs when a person's brain activity stops permanently. It is impossible to return to life after brain death.

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Chronic rejection
Slow failure of the transplanted organ.

A disease of the liver in which normal, healthy tissue is replaced with nonfunctioning tissue, and healthy, functioning liver cells are lost. Cirrhosis usually occurs when there is a lack of adequate nutrition, infection is present, or damage has been caused by alcohol abuse.

Cold Ischemia Time
The time an organ is without blood circulation - from the time the organ is removed from the donor to the time it is transplanted into the recipient.

Found in the urine, this waste product is measured to evaluate kidney function. An abnormally high creatinine level can indicate kidney disease and/or failure.

A laboratory blood test performed before the transplant to determine if the recipient's immune system will reject the donor organ. A "positive" crossmatch means the recipient's immune system produces antibodies against the donor blood type, and the transplant cannot be done because the antibodies would destroy the donor organ. The donor and the recipient are "incompatible." A "negative" crossmatch means there is no antibody reaction from the recipient's immune system, the donor organ is likely to be accepted by the recipient's immune system, and the transplant can move forward. See "virtual crossmatching."

A small piece of Velcro-like material that is bonded to many venous and peritoneal dialysis catheters. This material allows the body's tissues to grow directly into the cuff and reduce the chance of infections.

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Deceased Donor
A person who has been declared dead and whose organs and/or tissue have been donated to a transplant recipient.

A process to remove and neutralize antibodies so a transplant can occur without rejection. Patients can be desensitized using a combination of plasmapheresis, a procedure to remove antibodies, and a variety of specialized drugs.

The use of a machine to correct the balance of fluids and chemicals in the body and to remove wastes from the body when kidneys are failing. See hemodialysis and peritoneal dialysis.

In relation to organ and tissue transplantation and blood transfusion, this is the act of giving organ(s), tissue or blood, without compensation, to someone else.

Donation After Brain Death
Most of the organs used in transplants come from people who have suffered brain death as the result of an accident, heart attack or stroke. Brain death is total cessation of brain function, including brain stem function. There is no blood flow or oxygen to the brain; the brain no longer functions in any manner and will never function again.

Donation After Cardiac Death (DCD)
Some patients who have sustained traumatic brain injury cannot be declared dead based on the definition of brain death. In these cases, the patient is declared dead upon cardiac death, which is the cessation of cardiac and respiratory function when the patient is withdrawn from life support. Donation after cardiac death occurs only after the patient or family has decided to withdraw life-sustaining therapies for reasons entirely apart from any potential for organ donation.

Donor Card
A document that indicates a person's wish to be an organ donor.

Donor Pool
A group of people eligible to donate an organ.

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Swelling caused when the body retains too much fluid; also called "water weight."

The process of removing a clot from a dialysis fistula or graft to re-establish flow in the graft or fistula. This can be done surgically or using interventional radiological techniques.

End-stage Organ Disease
A disease that leads, ultimately, to functional failure of an organ. Some examples are emphysema (lungs), cardiomyopathy (heart), and polycystic kidney disease (kidneys).

End-stage Renal Disease (ESRD)
A very serious and life-threatening failure of the kidneys to remove waste (ultimately urine) from the body. This condition can be caused by many diseases such as diabetes, high blood pressure and glomerulonephritis, and is treatable with dialysis, where the waste is removed by a machine. However, the preferred treatment of ESRD is kidney transplantation. Transplantation offers patients "freedom" from dialysis, so they can lead a more normal lifestyle, and lengthens their lives.

Extended Criteria Donor (ECD)
An ECD kidney comes from a deceased donor who has additional risk factors, compared to other deceased donors, including age (over age 60 or age 50 with other risk factors), high blood pressure, death from stroke, and evidence of some prior kidney disease.

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A direct communication between an artery and a vein. A fistula can occur spontaneously, following trauma or surgically performed to establish dialysis access.

Foreign body
An entity that enters the body that is not supposed to be there, such as a germ, a piece of glass, a splinter, or a transplanted organ or tissue. The body normally attacks or tries to reject a foreign body to prevent further injury.

Happening very quickly and with intensity, for example, fulminant liver failure or fulminant infection.

Fungal Disease
An infection that usually occurs in patients during treatment with steroids or immunosuppressants. Examples of fungal infections include candida, aspergillus and histoplasmosis, which tend to be systemic infections.

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Genetic Disorder
A disease or disorder related to heredity, birth or origin.

Gingival Hypertrophy
Enlargement of the gums. It can be caused by some immunosuppressive drugs such as cyclosporine, and can usually be controlled by good oral hygiene and regular dental checkups.

Glomerular Filtration Rate (GFR)
A measurement of kidney function used to determine the severity of kidney disease.

A transplanted organ or tissue. A graft can also refer to prosthetic material used to connect blood vessels together for many reasons including dialysis access, to bypass a blockage, or to repair damaged vessels.

Graft Survival Rate
The percentage of patients who have functioning transplanted organs (grafts) at a certain point in time. The data are usually measured in one-, three- and five-year time periods.

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A form of renal replacement therapy (dialysis) where a person's blood is removed continuously and filtered through a machine that removes excess fluid and toxins. The filtered blood is then returned to the person. The procedure usually takes about 3 to 4 hours per session, and is usually done about three times per week.

A rapid loss of a large amount of blood; excessive bleeding.

Having to do with, or referring to, the liver.

An inflammation of the liver that can lead to liver failure.

Hepatocellular carcinoma
A liver tumor.

High Blood Pressure (Hypertension)
High blood pressure occurs when the force of the blood pushing against the walls of the blood vessels is higher than normal because the blood vessels have either become less able to stretch or have gotten smaller. High blood pressure causes the heart to pump harder to move blood through the body. High blood pressure can cause kidney failure and heart disease if not treated.

An excessive increase in hair growth. It is a common side effect of some drugs and can be controlled with waxing, hair removal creams or shaving.

Histocompatibility (HLA System)
The examination of human leukocyte antigens (HLA) in a patient, often referred to as "tissue typing" or "genetic matching." Tissue typing is routinely performed for all donors and recipients in kidney, pancreas and liver transplantation to help match the donor with the most suitable recipients to help decrease the likelihood of rejection of the transplanted organ.

Human Immunodeficiency Virus (HIV)
A virus that destroys cells in the immune system, resulting in the eventual inability of the body to fight off infections, toxins, poisons or diseases. HIV causes AIDS (acquired immunodeficiency syndrome), a late stage of the HIV infection that can include serious infections, blindness, some types of cancer and neurological conditions such as senility.

Human Leukocyte Antigens (HLA)
Molecules found on cells in the body that characterize each person as unique. These antigens are inherited from parents. In donor-recipient matching, HLA determines whether or not someone will accept an organ from a donor.

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Of, relating to, an organ being damaged or destroyed by a disease or condition of unknown origin.

Immune System
The organs, tissues, cells and cell products in the body that work to find and destroy foreign substances, such as bacteria, viruses and transplanted organs.

Immunosuppressive Drugs
Chemical agents that cause the human body not to produce antibodies that normally fight off foreign material in the body. The production of these antibodies needs to be suppressed in order to permit the acceptance of a donor organ by the recipient's body.

A condition that occurs when a foreign substance enters the body, causing the immune system to fight the intruder. Transplant recipients can get infections more easily because their immune systems are suppressed. It is more difficult for them to recover from infection, such as urinary tract infection, colds and the flu.

The swelling, heat and redness the body produces when it has an injury or infection.

Informed Consent
The process of reaching an agreement based on a full disclosure and full understanding of what will take place. Informed consent has components of disclosure, comprehension, competence and voluntary response. Informed consent often refers to the process by which one makes decisions regarding medical procedures, including the decision to donate the organs of a loved one.

Interventional Radiology
A subspecialty of radiologists who specialize in minimally invasive procedures that can be performed to establish dialysis access or to repair dialysis access that has failed or is not properly functioning.

Intravenous (IV)
Within a vein or veins; usually refers to medication or fluids that are infused into a vein through a plastic catheter (narrow tube) or "line" inserted into a vein.

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A pair of organs that maintain proper water and electrolyte balance, regulate acid-base concentration, and filter the blood of metabolic waste, which is excreted as urine. Kidneys can be donated and transplanted.

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Laparoscopic nephrectomy
An operation to remove a kidney using smaller incisions and instruments. Performed under general anesthesia, this minimally invasive approach offers many benefits compared to traditional open surgery. With smaller incisions, patients experience less pain, recover more quickly, return sooner to their normal activities, and have less visible scarring.

A white blood cell.

Surgically tying off a vessel with any type of suture material.

A large reddish-brown organ that secretes bile and is active in the formation of certain blood proteins and in the metabolism of carbohydrates, fats, and proteins. The liver can be donated and transplanted.

Living Donor
A person (unrelated or related to the transplant recipient) who donates a kidney while still alive. There are significant advantages to living donation: patients do not have to spend time on the organ waiting list and may never need to undergo dialysis. Living donor kidneys are often a better tissue match, and typically function longer - and work better - than deceased donor kidneys.

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The degree of compatibility, or likeness, between the donor and recipient.

MELD Score
The Model for End-Stage Liver Disease (MELD) score predicts the likelihood of survival while waiting for a liver transplant. The United Network for Organ Sharing (UNOS) computes the MELD Score, a numerical number, by taking into account three specific laboratory measurements: serum creatinene (measure of kidney function), serum biliruben (measure of liver function), and INR (measure of clotting function). The higher the score, the higher the risk of dying. The score is used to prioritize the organ waiting list so that the sickest people (that is, those with the highest MELD score) are transplanted first.

Metabolic Disorder
A condition or disease related to dysfunction in the chemical processes and activities of the body (i.e. metabolism).

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National Organ Transplant Act (NOTA)
Passed by Congress in 1984, NOTA initiated the development of a national system for organ sharing and a scientific registry to collect and report transplant data. It also outlawed the sale of human organs.

The functional unit of the kidney. Each kidney contains almost one million nephrons. This is where all the filtering of toxins and exchange of electrolytes and fluid occur.

New England Organ Bank (NEOB)
NEOB is the local (regional) organ procurement organization (OPO) for Beth Israel Deaconess Medical Center and the rest of New England, and coordinates sharing organs through UNOS. Staff at NEOB will enter a patient's medical information into a computer and will notify the transplant team when an organ becomes available based on the patient's waiting time on the list, blood type and size match.

New England Program for Kidney Exchange (NEPKE)
NEPKE is a New England Organ Bank program. In this paired exchange program, a patient who has a willing, but incompatible living donor can swap donor kidneys with a similar living donor/recipient pair.

Failure to follow the instructions of the medical team, such as not taking medicines properly or not attending clinic appointments. Noncompliance can lead to the failure of a transplanted organ.

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A part of the body, made up of various tissues, which perform a particular function. Transplantable organs are: heart, intestines, liver, lungs, kidneys, and pancreas.

Organ Preservation
Methods used to maintain the viability of organs between removal from the donor and transplantation into the recipient. These methods include preservation solutions, pumps and cold storage. Preservation times can vary from 2 to 48 hours depending on the type of organ being preserved.

Organ Procurement Organizations (OPO)
The OPO staff (transplant coordinators) coordinate activities relating to organ donation in states and regional areas throughout the U.S. Their activities include: evaluating potential donors, discussing donation with family members, arranging for the donation process (removal and transport of donated organs,) and educating the public about the need for donors.

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Long, irregularly shaped gland, which lies behind the stomach. Special glands in the pancreas secrete insulin. Pancreas transplants give patients with diabetes a chance to become independent of insulin injections. In addition to insulin, the pancreas secretes digestive enzymes (into the small intestine) that aid in the digestion of proteins, carbohydrates and fats.

Panel Reactive Antibody (PRA)
This is a blood test used to assess how a potential organ recipient will react to a donor organ. A patient with a PRA of 80 percent will likely reject 80 percent of donor kidneys. Patients with a high PRA have priority on the waiting list. The more antibodies in the recipient's blood, the more likely the recipient will react against the donor organ. For example, patients who have received multiple blood transfusions are likely to have more antibodies in their blood and a higher PRA.

Peritoneal Dialysis
A form of renal replacement therapy (dialysis) where a special fluid is flushed into the abdomen via a surgically placed tube. The fluid is allowed to sit (dwell) in the abdomen for a period of time. During this time, extra fluid and toxins from the body migrate into the abdominal fluid and are removed by emptying the fluid using the surgically placed tube.

A process is similar to dialysis, only it removes antibodies that are stored in blood plasma to make it possible to transplant organs even when the donor has a different blood type from the recipient.

Preemptive Transplantation
Kidney transplantation before a patient needs to go on dialysis. Patients who get a kidney transplant before dialysis usually do better overall than patients who are on dialysis who get a transplant. They live longer and the transplant itself lasts longer. In addition, most measures of quality of life (such as not feeling fatigued, returning to work) are better with a transplant compared to being on dialysis.

Itching related to liver disease, kidney disease, and/or drug reaction, among other causes.

Pulmonary Hypertension
Abnormally high blood pressure that occurs inside the pulmonary artery.

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A person who has received a transplant.

A problem where blood is not effectively removed from the body and passed through the dialysis machine. This blood will not have been cleaned of toxins and excess fluid. This results in poor dialysis. Recirculation is measured monthly in the dialysis units and should be less than 10 percent. If it is higher than 10 percent, it is likely related to problems with the dialysis access, such as a stenosis, or narrowing, of the connection, and may require treatment.

Rejection (Acute and Chronic)
The body's way of protecting itself against a foreign invader such as infectious germs. The body sees the transplanted organ or tissue as a foreign invader and attempts to destroy it. This can be acute and happen very quickly or chronic, which would be the slow failure of an organ to function. Anti-rejection (immunosuppressive) drugs help prevent rejection.

Having to do with, or referring to, the kidneys.

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Scientific Registry of Transplant Recipients (SRTR)
In 1987, Congress passed the National Organ Transplant Act that mandated the establishment of the Organ Procurement and Transplantation Network and SRTR. The purpose of the SRTR is to provide ongoing research to evaluate information about donors, transplant candidates and recipients, as well as patient and graft survival rates. The SRTR contains historical data from October 1, 1987 to the present. The registry tracks all transplant patients from the time of transplant through hospital discharge, and then annually for up to 3 years or until graft failure or death. URREA, University Renal Research and Education Association, operates the SRTR under contract with the Federal Government.

Having antibodies in the blood, which means a potential recipient will react against a greater number of potential organ offers. Sensitization is measured by panel reactive antibody (PRA). A highly sensitized patient is more likely to react against an organ and, therefore, has a smaller pool of potential organs that he/she may receive.

Side Effect
An unintended reaction to a drug.

Sleep Apnea
a disorder marked by shallow breathing, or brief pauses in breathing, while sleeping, resulting in daytime drowsiness.

Standard Criteria Donors (SCD)
A standard criteria donor kidney comes from a deceased donor who is declared brain dead.

A complication of a well-functioning graft or fistula in the arm where blood is preferentially diverted through the graft or fistula and does not reach the hand; that is, blood is "stolen" by the graft or fistula so it does not go down the arteries to the hand. This can lead to permanent muscle and nerve damage if not corrected. Correction usually requires ligation of the graft or fistula.

A narrowing that occurs along the course of a dialysis graft, fistula, artery or vein that causes a graft or fistula to clot or not function properly. This may need to be treated to improve dialysis if it is a severe stenosis.

Survival Rates
Survival rates indicate what percentage of patients are still living or grafts (organs) still functioning after a certain period of time.

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Tenchkoff (peritoneal dialysis) Catheter
A special silicone catheter that is surgically placed into the abdominal cavity for peritoneal dialysis. Fluid is added to the abdominal cavity and can be removed from the abdominal cavity using this catheter.

Tissue Typing
A blood test that helps evaluate how closely the tissues of the potential donor match those of the recipient.

Transplant Recipient
A person who has received a tissue or organ transplant.

The transfer of cells (e.g., stem cells), tissue or organs from one person to another, or from one area of the body to another.

Transplantation, Allogeneic (allograft)
Transplantation between genetically different members of the same species. Nearly all organ and bone marrow transplants are allografts. These may be between brothers and sisters, parents and children, or between donors and recipients who are not related to each other.

Transplantation, Autologous
Transplantation of an organism's own cell or tissues. This type of transplantation can be used to repair or replace damaged tissue. For example, autologous bone marrow transplantation permits the use of strong cancer therapies that can damage bone marrow. Once the treatment is completed, marrow that had been removed and not affected by the therapy is transplanted back into the patient.

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United Network for Organ Sharing (UNOS)
A nationwide umbrella for the transplant community; a non-profit organization that administers and maintains the Nation's organ transplant waiting list under contract with the Health Resources and Services Administration of the U.S. Department of Health and Human Services. Located in Richmond, Virginia, UNOS also brings together medical professionals, transplant recipients and donor families to develop organ transplantation policy.

A muscular tube that carries urine from the kidneys to the bladder. Each kidney has one ureter.

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A thin-walled blood vessel that carries unoxygenated blood from the tissues to the heart.

Vena Cava
The largest vein in the body. All unoxygenated blood returning to the heart from tissues enters this vein before returning to the heart.

Virtual Crossmatching
A computer-screening program to help match patients with the most suitable donors. Unlike crossmatching, which tests blood in a laboratory, virtual crossmatching is solely computer based. By evaluating a patient's know HLA antibodies, the computer can identify unacceptable or incompatible donor HLA antigens. Transplant professionals use this information to select recipients for donor organs that are likely to have a "negative" crossmatch (that is, no antibody reaction, for the best chance that a donor organ will be accepted by a recipient's immune system). A final "real" crossmatch is still always done before a transplant is performed.

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Waiting List (sometimes called a "wait list")
A national list that exists for all patients who are waiting for a transplant. It lists the total number of patients and the numbers of patients waiting for specific organs. It is used to locate the best recipient for a particular donated organ.

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An organ or tissue procured from an animal for transplantation into a human.

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Contact Information

Transplant Institute
Beth Israel Deaconess Medical Center
Lowry Medical Office Building, 7th Floor
110 Francis Street
Boston, MA 02215