Acute renal failure/acute kidney injury—Acute renal failure (also called acute kidney injury) means that the kidneys have suddenly stopped working. Kidneys remove waste products and help balance water and salt and other minerals (electrolytes) in the blood. When the kidneys stop working, waste products, fluids and electrolytes build up in the body.

Anemia—A quantitative deficiency of the hemoglobin, often accompanied by a reduced number of red blood cells and causing pallor, weakness and breathlessness.

Chronic kidney disease (CKD)—Chronic kidney disease, also called CKD, is a gradual reduction in kidney function that occurs over months or years, and results in the buildup of waste products. Stage 1 is mild; Stage 5 is renal failure.

Creatinine—A substance found in blood and urine produced normally by muscles, used to measure kidney function. High blood creatinine levels indicate depressed kidney function.

Diabetes—Diabetes is the most common disorder of the endocrine (hormone) system. Diabetes occurs when the body cannot regulate blood sugars.

Dialysis—The process of cleansing and achieving chemical balance in the blood of kidney failure patients. There are two types: hemodialysis and peritoneal dialysis (PD).

End stage renal disease (ESRD)—Severe kidney disease or chronic kidney failure that has reduced the kidney function to 10 percent or less of normal function, requiring the patient to have either dialysis or a transplant in order to live. Also called renal failure.

Hematuria—Hematuria means that red blood cells are in the urine. Urine does not normally contain red blood cells because the filters in the kidney prevent blood from entering the urine. In hematuria, the filters or other parts of the urinary tract allow blood to leak into the urine.

Hemodialysis—A method of dialysis in which blood is purified by circulating through an apparatus outside the body sometimes known as an "artificial kidney."

Histocompatibility—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 and pancreas transplantation to help match the donor with the most suitable recipients. This helps to decrease the likelihood of "rejecting" the transplanted organ.

Hypertension—Hypertension is high blood pressure. Blood pressure is the force of blood pushing against the walls of arteries as it flows through them. Arteries are the blood vessels that carry oxygenated blood from the heart to the body's tissues.

Hypotension—Hypotenstion is low blood pressure. This can occur if large amounts of fluid are removed from the blood vessels too quickly during dialysis. Hypotension can cause a fast pulse, dizziness, and sometimes nausea, vomiting or fainting.

Kidney—One of two bean-shaped organs that filter wastes from the blood. The kidneys are located near the middle of the back. They create urine, which is delivered to the bladder through tubes called ureters.

Kidney stones—An accumulation of minerals (e.g., calcium) in the kidney, which may lead to blockage and pain.

Nephrology—The science that deals with the kidneys, especially their functions and diseases.

Proteinuria—Proteinuria means that protein is in the urine. The kidneys act as filters and keep protein in the body. Very little or no protein normally appears in the urine.

Peritoneal dialysis (PD)—A procedure for treating advanced or permanent kidney failure. In peritoneal dialysis, a soft tube called a catheter is used to fill the abdomen with a cleansing liquid called dialysate. The solution pulls wastes and extra fluid into the abdominal cavity. These wastes and fluid then leave the body when the dialysate is drained.

Polycystic kidney disease (PKD)—Polycystic kidney disease (also called PKD) causes numerous cysts to grow in the kidneys. These cysts are filled with fluid. If too many cysts grow or if they get too big, the kidneys can become damaged. PKD cysts can slowly replace much of the kidneys, reducing kidney function and leading to kidney failure.

Red blood cells—Blood cells that carry oxygen from the lungs to the rest of the body.

Renal—Of or relating to the kidney.

White blood cells—Blood cells that fight infection; part of the immune system.