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Kidney Terms
Article posted in: Dialysis, Kidney Health

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Many people experiencing kidney problems feel overwhelmed and anxious about their situation. There are new rules, a myriad of tests, and lots of new jargon. Hopefully, this list of twenty kidney terms will help you navigate this new terrain with confidence. 

Kidney Terms

Metabolic Processes

The body is in a constant state of movement- even when it’s sitting still. It is constantly undergoing chemical reactions; using energy to break down substances for more energy. (1) These processes do, however, create toxic byproducts that the kidneys later filter from the body.

Nitrogenous Wastes

Nitrogenous wastes, formed through connecting with nitrogen, occur during the metabolic process. The main nitrogenous wastes are ammonia, urea, and uric acid. (2)

Estimated Glomerular Filtration Rate (eGFR)

eGFR is a formulation that determines the patient’s level of kidney function. It takes into account age, gender, race, body size, and serum (blood) creatinine levels. (3) Based on this equation, doctors will have an estimation of how well the kidneys are functioning and what steps the patient needs to take next.

Blood Urea Nitrogen (BUN)

Doctors use BUN levels as another measure of kidney function. This test measures the amount of the nitrogenous waste product, urea, in the bloodstream. (4)


Ammonia, a nitrogenous waste, is toxic to the body. Before it can be removed, however, it must be made nontoxic. To do this, the body uses the liver, which converts ammonia into urea. Then, urea is safely filtered and removed. (5)


Creatinine is a waste product that forms from everyday wear and tears on the body. Kidneys normally filter it from the blood and remove it. (6) This creates a baseline, making creatinine an excellent marker for kidney function. Creatinine is measured via blood or urine tests.

Uric Acid

High uric acid levels are another sign that kidneys may not be functioning properly. Uric acid forms when the body breaks down purines, nitrogenous compounds found in cells. When cells age and die, purines are released into the bloodstream. Normally, they are removed. High accumulations of uric acid can cause damage throughout the entire body. (7)


Albumin is a protein in the bloodstream. If the kidneys allow this protein into the urine, it’s a sign that they may be damaged. (8)


This is an important mineral found in bones. Usually, extra phosphorus is removed via the kidneys. When they are unable to remove the excess, phosphorus will pull calcium from the bones and make them weaker. Phosphates are also found in food products- particularly meat. People with kidney problems are usually recommended to watch their phosphate intake. (9)


Potassium is an important mineral and electrolyte found in food that helps the body’s muscles work. (10) When kidneys can no longer filter the extra potassium out of the body, it becomes toxic. 


The tiny units in the kidney that filter the blood. They are made up of a glomerulus, which filters the blood, and a tubule, that returns the clean blood. (11)

Vitamin D

Vitamin D supports strong bones and may help cardiovascular health, but it can’t be used by the body unless the kidneys convert it. Without the kidneys, this important substance couldn’t be used by the body. (12)

Erythropoietin (EPO)

A hormone produced by the kidney that stimulates the production of red blood cells. A low functioning kidney will not create enough of this hormone, explaining why some kidney patients get anemia. (13)

Renal Dietician

Board-certified renal dieticians assist kidney patients with their diet. They create specialized plans based on their client’s individual lab results.

Peritoneal Dialysis

This type of dialysis uses the stomach lining, called a peritoneum, to filter the blood from inside the body. (14)


Once a kidney stops functioning, some people choose to go onto dialysis. Once this decision is made, doctors may choose to create a fistula for dialysis. A fistula, in this case, connects the artery flows to the vein that the dialysis machine works through. (15)


Hemodialysis uses a machine to filter toxins from the blood. It hooks up to the fistula, which provides a steady flow of blood to the machine. (16)

Intravenous Pyelogram (IVP)

This is a type of x-ray that allows doctors to see kidney damage. It utilizes a special dye. (17)


The surgical procedure of removing either both kidneys, one kidney, or partial kidney. (18)


Yes, we snuck Renadyl™ on here. That’s because the patented microbes in Renadyl™ may help with a lot of the terms discussed here. These beneficial bacteria (probiotics) can metabolize (consume) nitrogenous toxins like creatinine and urea.* (19) The body is then able to remove the toxins- not through urine, but during bowel movements. This action may stabilize eGFR and could improve Quality of Life!* (20)

Did we miss any terms that you’d like covered? Leave a comment or let us know on Facebook, Instagram, or Twitter. 

Works Cited

(1) 24.1 Overview of Metabolic Reactions. (2013, March 6). Retrieved from

(2) Types of Nitrogenous Waste. (n.d.). Retrieved from

(3) Henderson, J. (2020, January 27). eGFR – Understanding your lab values. Retrieved from

(4) Urea. (n.d.). Retrieved from

(5) Liu, X., Wang, H., Liang, X., & Roberts, M. S. (2017). Chapter 30- Hepatic Metabolism in Liver Health and DiseaseVersion (Elsevier Inc.). In Liver Pathophysiology Therapies and Antioxidants. Retrieved from

(6) Creatinine: What is it? (2017, March 1). Retrieved from

(7) Uric Acid. (n.d.). Retrieved from

(8) Albuminuria: Albumin in the Urine. (2016, October 1). Retrieved from

(9) Phosphorus and Your CKD Diet. (2019, August 30). Retrieved from

(10) High potassium (hyperkalemia). (n.d.). Retrieved from

(11) Your Kidneys & How They Work. (2018, June 1). Retrieved from

(12) Vitamin D: The Kidney Vitamin? (2017, March 3). Retrieved from

(13) Erythropoietin. (n.d.). Retrieved from

(14) Peritoneal Dialysis. (2018, January 1). Retrieved from

(15) Henderson, J. (2020, January 31). Keeping your fistula running for years to come. Retrieved from

(16) Henderson, J. (2020, March 26). Moving to Home Hemodialysis. Retrieved from

(17) IVP – Intravenous Pyelogram. (n.d.). Retrieved from

(18) Nephrectomy. (n.d.). Retrieved from

(19) Ranganathan N (2018) Reality of “Enteric Dialysis ®” with Probiotics and Prebiotics to Delay the Need of Conventional Dialysis. J Nephrol Ther 8: 319. doi:10.4172/2161-0959.1000319

(20) Ranganathan Natarajan, et al. “Quality of Life in Chronic Kidney Patients Using a Synbiotic Dietary Supplement: a Survey”