Glossary of Definitions


Abdomen The part of the body that contains the internal organs between the pelvis and the chest cavity.

Access A means to get into the body. Accesses to the bloodstream for hemodialysis are fistulas, grafts, etc. Access to the peritoneal cavity for peritoneal dialysis is a catheter.

Angiotensin-converting enzyme inhibitor (ACE inhibitor) Medicine used to treat high blood pressure. ACE inhibitors can also help prevent or slow kidney damage.

Acute Rapidly developing; severe; short duration.

Acute renal failure A sudden and severe decrease in kidney function that may be short term.

Albumin A protein in blood plasma that acts as a carrier and helps to maintain blood volume and blood pressure.

Albuminuria A condition in which albumin is present in the urine. There are filters in the kidneys that prevent large molecules, such as albumin, from passing through. If these filters are damaged, albumin passes from the blood into the urine.

Albumin creatinine ratio (ACR) A test that compares the amount of albumin in the urine with the amount of creatinine. It is used to detect whether albuminuria is present.

Allograft An organ or tissue transplant from one person to another.

Alport syndrome An inherited condition that results in kidney disease. It generally develops in childhood and is more serious in boys than in girls.

Ambulatory Able to walk; movable.

Analgesic-associated kidney disease A condition in which there is a loss of kidney function due to long-term use of analgesic (pain-relieving) medications. Analgesics that combine aspirin and acetaminophen are most dangerous to the kidneys.

Anemia A condition in which there is a reduction of red blood cells.

Antibiotic Medication used to kill bacteria and fight infection.

Antibodies Proteins that are made by the immune system, the body's defense mechanism, to attack substances that are not normally part of a person’s body—for example, bacteria or toxins.

Anticoagulant Medication that delays or stops the clotting of blood, such as Coumadin or heparin.

Antigen A toxin or other foreign substance that causes a person’s body to create an immune response.

Antihypertensive Medication that lowers blood pressure.

Antiseptic A chemical that stops growth and reproduction of bacteria and viruses, but doesn’t necessarily destroy them as a disinfectant would.

Anuria A condition in which a person stops making urine.

Arterial line A tube that carries blood away from the body into the artificial kidney.

An age-related condition in which the arteries become stiff and calcified.

Artery A blood vessel that carries blood away from the heart to other parts of the body.

Artificial kidney
A filtering device that is used to remove excess fluid and waste products from the body. Also known as a “dialyzer” or a “hemodialyzer.”


Bacteria Single-cell organisms, capable of rapid reproduction. They are present everywhere. Some are harmless, while others are known to produce infectious diseases.

Bath (see “dialysate”)

Biopsy A procedure in which a tiny piece of a tissue from a body part, such as the kidney or bladder, is removed for examination under a microscope by a pathologist.

Bladder A muscular, elastic sac or membrane inside the body that stores the urine.

Blood chemistry The measurement of certain chemicals in the blood.

Blood flow rate The rate at which the patient’s blood is pumped through the artificial kidney during dialysis.

Blood group A type of human blood. Blood groups are classified by the ABO system (A, B, AB and O). In any of the 4 ABO groups, a person can be RH positive or RH negative, meaning that a person can be classified as one of the 8 possible types (O+, O-, A+, A-, B+, B-, AB+ or AB-). Classifying blood type is important for working out compatibility for blood transfusions and organ transplantations.

Blood pressure
The pressure blood exerts on the walls of the blood vessels. This is expressed in 2 numbers, such as 120/80. The systolic (top) number is the pressure when the heart is contracting and the diastolic (bottom) number is the pressure when the heart is at rest.

Blood pump A pump that moves blood from the patient’s access through the blood tubing and artificial kidney and back to the patient without damage to the blood cells.

Blood urea nitrogen (BUN) A way to measure the combination of waste products (nitrogen and urea) in the blood normally excreted by the kidneys.

Blood vessels The tubes that take blood around the body.

Bruit The sound produced by the blood flowing through a blood vessel, as well as through a fistula, graft or shunt.


Cadaveric donor Someone who has died and whose tissues or organs, such as kidneys, have been donated for transplantation into another human.

Calcium A chemical that is important for bone growth and formation, blood clotting, nerve and muscle functioning and the activation of certain enzymes.

Carbohydrate A category of food compounds that is easily used by the body for energy.

Cardiac Anything to do with the heart.

Cardiovascular disease (CVD) All diseases and conditions of the heart and blood vessels, including heart attack, heart failure, stroke, blockages in the blood vessels and vascular kidney disease.

Catheter A flexible, hollow tube through which fluids enter or leave the body. For peritoneal dialysis, a catheter is placed by a doctor in the abdomen (peritoneal cavity). For hemodialysis, a venous catheter may be placed in the neck, chest or leg as a short-term solution. A fistula or a graft is the preferred access type for hemodialysis.

A naturally occurring, waxy substance made by the body. It is an essential building block of cell membranes, hormones and vitamin D. Too much cholesterol in the blood can cause clogging of the arteries and can lead to cardiovascular disease.

Chronic Persisting for a long period of time or recurring often.

Chronic kidney disease (CKD) A term used widely to describe kidney damage or reduced kidney function (regardless of the cause) that persists for more than 3 months. Sometimes CKD leads to kidney failure, which requires dialysis or a kidney transplant to keep a person alive.

Chronic renal (kidney) failure
Damage to the kidneys that is usually progressive in nature and cannot be reversed, reducing the filtration and waste removal functions of the kidneys.

Clearance The rate that waste products in the blood are removed through dialysis, expressed in milliliters per minute.

Coagulation The process of forming a blood clot.

Concentration The strength of a solution.

Congestive heart failure (CHF) A condition in which the body is overloaded with fluid, causing the heart to pump less effectively. Congestive heart failure may result in excess fluid in the lungs.

Contaminate Allowing microorganisms to contact a sterile area, making the area unsterile and creating the potential for infection.

Continuous ambulatory peritoneal dialysis (CAPD)
A form of dialysis in which dialysate drains into and out of the peritoneal cavity by gravity several times a day.

Continuous cycling peritoneal dialysis (CCPD) A form of dialysis that uses a cycling machine to infuse and drain dialysate from the peritoneal cavity several times during the night while the patient sleeps.

Involuntary muscle contractions and relaxation.

Creatinine One of the many waste products in the blood that is produced by normal tissue breakdown and removed by the kidneys or by dialysis in patients with renal failure.

Cross matching
The testing of blood and tissues to check the compatibility of a donor’s kidney and a person in need of a kidney transplantation.

Culture A sample of organisms taken from a site to identify the specific organism that is causing infection.

Cyst An abnormal sac containing gas, fluid or a semisolid material. Cysts may form in kidneys or in other parts of the body.

Cystine An amino acid found in blood and urine. Amino acids are building blocks of protein.

Cystine stone A rare form of kidney stone consisting of the amino acid cystine.


Diabetes A chronic disease caused by problems with the production and/or action of insulin in the body. 

Diabetic nephropathy The medical name for kidney disease caused by diabetes.

Dialysate A solution consisting of water and chemicals (electrolytes) that passes through the artificial kidney to remove excess fluids and waste products from the blood. Also called “bath.”

Dialysate flow rate The rate at which dialysate flows through the dialyzer.

Cleansing the body of unwanted toxins, waste products and excess fluids by filtering them from the blood through a semipermeable membrane.

Dialysis fluid (see “dialysate”)

Dialysis treatment plan A plan that is based on the individual needs of a person with end stage renal disease (ESRD) to reestablish physical balance.

Dialyzer (see “artificial kidney”)

An important member of a treatment team. A dietitian can help a person manage their kidney health (and other things like blood pressure) through dietary changes.

Diffusion Passage of particles from a solution of high concentration to a solution of low concentration, resulting in an even distribution of particles.

Disinfectant An agent that kills most microorganisms, like bacteria and viruses, it contacts.

A type of medicine that helps the body get rid of extra fluid. Having too much fluid in the body can raise blood pressure.

Donor A person who gives a body organ, such as a kidney, to another person. For kidneys, the donor can be living or deceased.

Dry weight The weight of a dialysis patient when excess fluid has been removed. Also known as “ideal weight.”

Dwell time The length of time dialysate (dialysis solution) stays in the peritoneal cavity during peritoneal dialysis.


Swelling or puffiness due to buildup of excess fluid in the tissues, which is most noticeable in ankles, hands and face. It occurs in dialysis patients as a result of excess fluid intake or decreased ultrafiltration.

End stage renal disease (ESRD)
Total and permanent kidney failure. When the kidneys fail, the body retains fluid and harmful waste builds up. A person with ESRD needs treatment to replace the work of the failed kidneys.

Erythropoietin (EPO)
A body chemical (hormone) mainly made by the kidneys that causes the bone marrow to make red blood cells. A lack of this hormone can cause anemia.

Estimated glomerular filtration rate (eGFR)
A test to measure how well the kidneys are cleaning the blood, which helps to determine the stage of kidney disease. eGFR is reported in milliliters per minute and is usually estimated from the results of the creatinine blood test along with age and gender. 

Exchange The process of changing used dialysate for fresh solution in peritoneal dialysis.

Exit site The area where the needles enter or exit through the access. Also, where a peritoneal dialysis catheter or subclavian catheter exits the skin.


Fistula A type of access that is created by surgically joining an artery and a vein so that the vein enlarges due to the flow of arterial blood. 

Fluid allowance/restriction
The amount of fluid that is permitted each day, which is usually set by a doctor.

Fluid overload The point at which extra fluid in the body causes edema, difficulty in breathing or extra strain on the heart.

Fluid retention (see “edema”)


Glomerular filtration rate (GFR) (see “estimated glomerular filtration rate”)

Glomerulonephritis Inflammation of the glomeruli, the kidneys’ filters.

A tiny set of blood vessels in the nephron.

Glucometer A small machine that is used to test blood sugar levels and can be used at home.

Glucose The main sugar found in blood. The body turns many foods into glucose. This is the body’s main source of energy.
Glucose tablet A small, chewable tablet made of glucose. If a person’s blood sugar drops too low, they can eat a glucose tablet to bring it back up to a healthy range.

Graft The surgical placement of a material between an artery and vein to create a circulatory access for hemodialysis. Graft can also refer to a transplanted kidney.


Hematocrit The ratio of red blood cells to total blood.

A condition in which blood is present in the urine. Blood that is visible in the urine is called gross hematuria. Blood that cannot be seen by the naked eye and can only be seen when examined by a microscope is called microscopic hematuria.

Hemodialysis The removal of excess fluids and waste products by passage of blood through an artificial kidney.

Hemodialyzer (see “artificial kidney”)

The protein portion of the red blood cell, which carries oxygen from the lungs to the rest of the body’s tissues.

A “blood thinner,” or anticoagulant, that is given in hemodialysis to slow clotting time in order to prevent blood from clotting in the lines or dialyzer.

Inflammation of the liver caused by virus, bacteria, toxic agents or medication.

Hepatitis B surface antigen A substance that indicates infection with hepatitis B virus. This virus can cause serious liver damage and can complicate chronic kidney disease (CKD) as well as treatment for CKD. Testing for the hepatitis B surface antigen may be performed on both the treatment team and patients.

Hepatitis C surface antigen A substance that indicates infection with hepatitis C virus. This virus can cause serious liver damage and can complicate chronic kidney disease (CKD) as well as treatment for CKD. Testing for the hepatitis C surface antigen may be performed on both the treatment team and patients.

High-density lipoprotein (HDL)
Also called “good cholesterol”. HDL carries cholesterol to the liver where it can be removed from the blood. An HDL level of more than 40 is considered good. An HDL level of more than 60 is even better.

A natural chemical produced in one part of the body and released into the blood to trigger or regulate particular functions of the body. The kidney releases 3 hormones: erythropoietin, renin and an active form of vitamin D that helps regulate calcium for bones.

Hyperoxaluria An unusually large amount of oxalate in the urine, which can lead to kidney stones.

Hypertension High blood pressure.

Hypotension Low blood pressure.


Ideal weight (see “dry weight”)

Immune system The body’s system for protecting itself from viruses and bacteria or any foreign substances.

Immunosuppressant A drug that suppresses the body’s immune response. It is given to transplant recipients to help prevent rejection of the transplanted kidney.

Infection The invasion of the body by disease-producing organisms and the reaction of the body’s tissues to their presence.

Inflammation Heat, redness, swelling and pain that can be present in parts of the body or throughout the body; inflammation is usually a result of infection or irritation.

Insulin A hormone that helps a person’s body turn the sugar they’ve eaten into energy. In diabetes, the body either doesn’t make or use insulin correctly.

Interstitial nephritis
Inflammation of the kidney cells that are not part of the fluid-collecting units, a condition that can lead to acute renal failure or chronic kidney disease.

Intravenous Being within a vein.

Intravenous pyelogram (IVP)
An X-ray of the urinary tract. A dye is injected into the body to make the kidneys, ureters and bladder visible on the X-ray and show any blockage in the urinary tract.


Kidney One of two bean-shaped organs located at the back of the abdominal cavity, one on each side of the spinal column. Kidneys maintain the body’s chemical balance by excreting waste products and excess fluid in the form of urine.

Kidney disease Permanent damage to the kidneys. The most common causes are diabetes and high blood pressure. If left untreated, kidney disease can lead to kidney failure.

Kidney failure When the kidneys don’t work well enough to clean the blood. Someone with kidney failure will need dialysis or a kidney transplant to live.

Kidney stone A stone that develops from crystals that form in urine and build up on the inner surfaces of the kidney, in the renal pelvis or in the ureters.

Kidney transplant
When a healthy kidney from a person is placed in someone else whose kidneys have failed. A kidney transplant can come from a living donor or from someone who has just died.

Kilogram 1,000 grams; 1 kilogram is equal to 2.2 pounds.

Kt/V Clearance x time / volume. A measurement that indicates how well waste products have been removed by dialysis treatment.


Lipid Fatty substances, including cholesterol and triglycerides that are present in blood and body tissues. 

Liter The basic unit of volume measurement in the metric system, approximately equal to a quart.

A method of breaking up kidney stones using shock waves or other means.

Living donor A person who donates an organ while they are still alive.

Low-density lipoprotein (LDL) Also called “bad cholesterol”. A high LDL level puts a person more at risk for kidney disease, heart disease and stroke. A normal LDL level is generally less than 100. 

Lupus nephritis Inflammation of the kidneys caused by an autoimmune disease called systemic lupus erythematosus. The condition can cause hematuria and proteinuria and may progress to end stage renal disease.


Medical nutrition therapy (MNT) The use of nutrition to help control chronic conditions like diabetes, heart disease or kidney disease. MNT includes working with a dietitian to make healthy changes to a person’s diet.

Membrane A thin layer of tissue or material, usually an outer layer or lining of organs or group of organs.

Membranous nephropathy (MN) A disorder that hinders the kidneys’ ability to filter waste products from the blood because of harmful deposits on the glomerular membrane. Some cases of membranous nephropathy develop after an autoimmune disease or malignancy.

Metabolism The physical and chemical changes in your body that produce and use energy.

Minerals Inorganic substances that are necessary for normal body function, but are toxic in high concentrations.

Monitor (noun) An electronic device that is used to check, remind or warn. (verb) Watching patients during their treatments or checking the adequacy of treatments over time.


Nausea The feeling a person experiences when they have an upset stomach.

Nephrectomy The surgical removal of a kidney.

Nephrologist A doctor who specializes in kidney disorders.

Nephropathy Any disease of the kidney.

Nephron A unit of the kidney that maintains the body’s chemical balance. There are approximately one million nephrons in each kidney.

Nephrotic syndrome A collection of symptoms that indicate kidney damage. Symptoms include high levels of protein in the urine, a lack of protein in the blood and high blood cholesterol. 

Neuropathy Any disease of the nerves.


Oedema (see “edema”) 

Organs Parts of the body that are needed to stay alive, such as the kidneys, heart, lungs and liver.

Osmosis Movement of fluid through a semipermeable membrane to achieve equal concentration on both sides of the membrane.

Oxalate A chemical that combines with calcium in urine to form the most common type of kidney stone (calcium oxalate stone).


Palpitation The physical symptom a patient feels due to arrhythmia, an irregular beating of the heart.

Parathyroid glands Small glands located in the neck that produce a hormone that is necessary to regulate calcium and phosphorus levels in the blood.

Parathyroidectomy The partial or complete surgical removal of the parathyroid glands.

PD Plus A combination of CCPD and CAPD mostly used by peritoneal dialysis (PD) patients who need more efficient dialysis.

Pericarditis Inflammation of the pericardium, the sac-like structure surrounding the heart.

Peritoneal cavity The space surrounding the abdominal organs located under the abdominal muscles.

Peritoneal dialysis (PD) A form of dialysis in which the lining of the abdomen, the peritoneal membrane, acts as a natural filter.

Peritoneum The smooth, semipermeable membrane that covers the abdominal organs and lines the abdominal cavity.

Peritonitis An infection of the peritoneal cavity that must be treated immediately by a doctor.

Phosphate binders Medications that bind with dietary phosphorus in order to eliminate the phosphorus from the body, which helps keep calcium and phosphorus levels in balance for dialysis patients.

Phosphorus An element that is necessary for normal body functions, especially bone formation.

Polycystic kidney disease (PKD) A hereditary disease that involves the growth of cysts on kidney tissue.

Potassium An element that is needed by the body for normal muscle and nerve function as well as cell maintenance.

Proteins Groups of nitrogen-containing compounds found in the body that are essential to life.

Proteinuria The presence of too much protein in a person’s urine.

Pruritus A condition in which a person’s skin is severely itchy.

Pulse The throbbing sensation felt in the arteries in time with the heartbeat.


Red blood cell A type of blood cell that contains hemoglobin and carries oxygen to the body’s tissues.

Renal Relating to the kidneys. For example, a renal disease is a disease of the kidneys.

Renal cell carcinoma A type of kidney cancer.

Renal cysts Abnormal fluid-filled sacs in the kidney that range in size from microscopic to much larger. Many simple cysts are harmless, while other types can seriously damage the kidneys.

Renal diet A special diet for dialysis patients to help them stay healthy and feel their best.

Renal function Kidney function.

Renal nuclear scan A test of the structure, blood flow and function of the kidneys. During a renal nuclear scan, the doctor injects a mildly radioactive solution into a person’s arm vein and uses X-rays to monitor the solution’s progress through their kidneys.

Renal osteodystrophy Weak bones caused by poorly working kidneys. Renal osteodystrophy is a common problem for people on dialysis who have high phosphate levels or insufficient vitamin D supplementation.

Renal replacement therapy Another name for dialysis, a treatment option for people with kidney failure that involves removing waste and excess fluid from the body.

Renal tubular acidosis (RTA) A defect in the kidneys that hinders their normal excretion of acids. Failure to excrete acids can lead to weak bones, kidney stones and poor growth in children.

Renal vein thrombosis (RVT) A condition in which blood clots in the vessel that carries blood away from the kidneys. This can occur in people with nephrotic syndrome.

Renin A hormone made by the kidneys that helps regulate the volume of fluid in the body and blood pressure.


Semipermeable membrane A material that allows fluids and small particles to flow through it but not larger particles.

Sodium An element found in the body that helps regulate the body’s fluid content.

Sterile Totally free from any living microorganisms.

Struvite A mineral found in kidney stones that were caused by an infection.

Systolic pressure The first and highest number in the two-part blood pressure measurement. It measures the highest pressure in the arteries when the heart beats (the heart muscle contracts).


Thrill  A fine vibration or buzzing over an area of high or turbulent blood flow in the body.

Tissue typing Matching the blood cells of a potential transplant recipient with the blood cells of potential donors.

Toxin A waste product in the blood or any substance that is poisonous.

Transplant The replacement of a diseased organ with a healthy one. A kidney transplant may come from a living donor or from someone who has just died.

Triglycerides A type of protein in the blood. Normal triglycerides are less than 150. High triglycerides can raise a person’s risk of heart disease or kidney disease. 

Ultrafiltration A process used to remove excess fluid from the blood during dialysis.

Ultrasound A technique that bounces safe, painless sound waves off organs to create an image of their structure.

Urea A nitrogenous waste product that is formed during the breakdown of protein in the body.

Urea reduction ratio (URR) A percentage that is based on how much blood urea nitrogen (BUN) was removed during a dialysis treatment. It indicates how effectively urea and other waste products have been removed.

Uremia The buildup of waste products in the blood due to the inability of the kidneys to eliminate them.

Ureters Tubes that carry urine from the kidneys to the bladder. 

Urethra The tube that carries urine from the bladder to the outside of the body.

Uric acid stone A kidney stone that may result from a diet that is high in animal protein. When the body breaks down this protein, uric acid levels rise and can form stones.

Urinalysis A test of a urine sample that can reveal many problems of the urinary system and other body systems. The sample may be observed for color, cloudiness and concentrations; signs of drug use; chemical composition, including sugar; and the presence of protein, blood cells, germs or other signs of disease.

Urinary tract The system that takes waste products from the blood and carries them out of the body in the form of urine. The urinary tract includes the kidneys, renal pelvises, ureters, bladder and urethra.

Urinary tract infection An illness caused by harmful bacteria growing in the urinary tract.

Urinate To release urine from the bladder to outside the body.

Urine A liquid waste product that is filtered from the blood by the kidneys, stored in the bladder and expelled from the body through the urethra by the act of voiding or urinating.


Vascular Pertaining to blood vessels.

Vein A blood vessel that carries blood from other parts of the body back to the heart.

Venous Referring to veins and the flow of blood to the heart.

Venous line A tube that carries blood from the dialyzer back to the body.

Void To urinate and empty the bladder.


Waste products Substances that are formed from the breakdown of protein in foods and from normal muscle activity.

Wegener’s granulomatosis (WG) An autoimmune disease that damages the blood vessels and causes disease in the lungs, upper respiratory tract and kidneys.

White blood cell A type of blood cell that fights infection in the body.