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For Patients & Families: About Your Kidneys

about your kidneys

The kidneys are a pair of bean shaped organs whose job it is to filter your blood. Each kidney is about the size of an adult fist, and they are located on either side of the spine, just below the rib cage. Although they are small, your kidneys perform many complex and vital functions that keep the rest of the body in balance. For example, kidneys:


  • Help remove waste and excess fluid

  • Filter the blood, keeping some compounds while removing others

  • Control the production of red blood cells

  • Make vitamins that control growth

  • Release hormones that help regulate blood pressure

  • Help regulate blood pressure, red blood cells, and the amount of certain nutrients in the body, such as calcium and potassium.

Amazingly, all of the blood in your body passes through your kidneys several times a day.

kidney facts

  • Why are the kidneys so important?
    Your kidneys perform important functions that affect every part of your body. In fact, many other organs depend upon the kidneys to function normally. The kidneys perform complicated jobs that keep the rest of the body in balance. When the kidneys become damaged, your body’s other organs are affected as well. The major job of the kidneys is to remove waste products and extra fluids from the body in the form of urine. The production of urine is a complicated process that maintains a chemical balance in your body. Your kidneys also regulate your body’s salt, potassium and acid content, and make hormones that affect the way your other organs function. One hormone produced by the kidneys is needed to make red blood cells. Others help regulate your blood pressure and help your body use calcium. Your kidneys also: Remove waste products from your body Balance chemicals in your body, such as potassium, phosphorus, calcium, and sodium Balance your body’s fluids Regulate your blood pressure Promote strong, healthy bones
  • How do your kidneys work / function?
    Each of your two kidneys contains about one million functioning units called nephrons. A nephron consists of a filtering unit of tiny blood vessels, called a glomerulus, which is attached to a tubule. When blood enters the glomerulus, it is filtered and the remaining fluid then passes through the tubule. In the tubule, chemicals and water are either added to or removed from this filtered fluid according to the body's needs. The final product is urine, which we excrete. The kidneys perform their life-sustaining job of filtering and returning to the bloodstream about 200 quarts of fluid every 24 hours. Approximately two quarts are eliminated from the body in the form of urine, and about 198 quarts are retained in the body. The urine we excrete has been stored in the bladder anywhere from 1 to 8 hours.
  • What is chronic kidney disease?
    Chronic kidney disease (CKD) means the kidneys are damaged. When the kidneys are damaged, they cannot filter blood and do their other jobs well enough. Protein in the urine for three months or longer is a warning sign of kidney damage. Your level of kidney function is measured by the test for glomerular filtration rate (GFR). A GFR of less than 60 for three months or more indicates CKD.
  • What are some of the types and causes of kidney disease?
    There are many types of kidney disease, and it usually affects both kidneys. If the kidneys' ability to filter the blood is damaged by disease, wastes and excess fluid may build up in the body, causing severe swelling and symptoms of kidney failure. The kidneys may be affected by diseases such as diabetes and high blood pressure. Some kidney diseases are inherited Other diseases are congenital; that is, individuals may be born with an abnormality that can affect their kidneys. The following are some of the most common types and causes of kidney disease: Diabetes is the leading cause of serious kidney disease. High blood pressure (also known as hypertension) is another common cause of kidney disease. Glomerulonephritis is a disease that causes inflammation of the kidney's tiny filtering units, the glomeruli. Polycystic kidney disease is the most common inherited kidney disease. Kidney stones are a common kidney malady that can cause further damage to the kidneys if they are not treated. Urinary tract infections occur when bacteria enter the urinary tract and cause symptoms such as pain and/or burning during urination and more frequent need to urinate. Congenital diseases such as Goodpasture's Syndrome and Reflux Disorder may also affect the kidneys. Overuse of over-the-counter medications and the use and buildup of illegal drugs in the body can cause kidney failure. To learn more about kidney disease, please click here.
  • How is kidney disease detected?
    Early detection and treatment can slow or prevent the progression of kidney disease. Some simple tests can be done to detect early kidney disease. They are: Blood pressure monitoring. High blood pressure is a cause of kidney disease. It may also be a sign of kidney trouble. A test for protein in the urine. Too much protein in your urine may mean that your kidneys’ filtering units have been damaged. A single positive result could be due to a fever or heavy exercise, so your doctor will want to confirm your urine protein test results over several weeks. An estimate of your Glomerular Filtraion Rate (GFR) to show how much kidney function you have. Your doctor uses the results of a blood test, along with your age, gender, and race, to estimate your GFR number. This number tells your doctor how much kidney function you have. As CKD progresses, your GFR number decreases. A completely healthy kidey function is measured at a GFR of around a 100, which means that the kidneys are working at 100 percent. Your kidney function is still considered normal if the GFR number is 90 or greater. Here's a way to understand the GFR scale: If your GFR is 45, you know that your kidneys are working at approximately 45 percent of the normal rate. It is very important that people who are at increased risk for kidney disease have these tests.
  • Can kidney desease be treated?
    Many kidney diseases can be treated. Careful control of diseases like diabetes and high blood pressure can help to prevent kidney disease or slow its progression. Kidney stones and urinary tract infections often can be treated successfully. Unfortunately, the exact causes of some kidney diseases are still unknown, and specific treatments are not yet available. Sometimes these diseases progress to chronic kidney failure, requiring dialysis or kidney transplantation. Changes in diet and treatment for high blood pressure sometimes help to slow the progression of these diseases. Research is being conducted to find more effective treatment for these diseases.
  • If I have chronic kidney disease, do I need dialysis?"
    Ultimately, dialysis is treatment option that is entirely up to the patient. Normally, dialysis is not considered as a treatment option unless a patient is expereincing end-stage kidney failure (which usually occurs when a patient loses about 85 to 90 percent of their kidney function, and they have a GFR of less than 15). If you are not in end-stage kidney failure, your physician will likely work to slow, or control, the cause of your kidney disease. Treatment options vary, depending on the cause. But kidney damage can continue to worsen even when an underlying condition, such as high blood pressure, has been controlled. Your doctor will likely also work to treat any complications that arise from kidney disease. Treatments may include: High blood pressure medications Medications to lower cholesterol levels Medications to treat anemia Medications to relieve swelling Medications to protect your bones A lower protein diet to minimize waste products in your blood
Kidey Facts


kidney a - z health guide

To learn more about topics related to kidney health

 please visit our national office's Kidney A - Z Health Guide by clicking the links below. 

kidney vocabulary list

There's a lot of terminology in medicine, kidney health, and treatment/care. Here's a handy, simple list to help you follow the conversation. 

  • Bladder:​ A sac in your body that holds the urine (pee) produced by the kidney.


  • Blood pressure:​ The force of blood pushing against the inner walls of the blood vessels.


  • High blood pressure:​ Also called Hypertension. This means the force is too high (higher than 120/80).


  • Chronic: Health conditions that cause some long-term health problems.


  • Chronic Disease: A disease or disorder that lasts many years (or forever) and may get worse over time.


  • Diabetes: A disorder in which the body cannot make insulin or cannot use it properly. Insulin is a hormone that controls how much sugar is in your blood.


  • Dialysis: A procedure that filters waste products and extra water from your blood. It is one of the main treatments for kidney failure.


  • GFR (glomerular filtration rate): A measure of kidney function. It tells you how well your kidneys work.

  • InheritedSomething you were born with and get from your mother or father, like red hair or blue eyes.


  • Kidneys: Two bean-shaped organs in your body. Kidneys clean the blood, help make red blood cells, and keep bones healthy.


  • Kidney Disease: The loss of some kidney function. It means your kidneys cannot work as well as healthy kidneys. Kidney disease can be treated.


  • Kidney Failure: The loss of all kidney function. It means your kidneys have stopped working. You will need a kidney transplant or dialysis treatment for the rest of your life.


  • Organ: A part of your body that does an important job. For example, the heart, kidneys, and liver are organs.


  • Red Blood Cells: Cells in your blood that carry oxygen to all parts of your body.


  • Renal: Having to do with the kidneys.


  • Renal Function: Kidney function.

  •  Risk factors: Something that increases your risk. For example, diabetes increases your risk for kidney disease.


  • Symptoms: A change in your body that alerts you that something is wrong. It may mean you have an illness or disease.


  • Treatment Plan: A plan of medical care to help you get well, or to keep an illness or disease from getting worse.


  • Transplant: An operation to put a healthy organ in your body.


  • Uterus: Two tubes that carry urine (pee) from the kidney to the bladder.


  • Urethra: A tube that carries urine (pee) out of the bladder when you go to the bathroom.


  • Urinary System (also called “Urinary tract”): A system in your body that includes the kidneys, ureters, bladder, and urethra. It acts as a plumbing system to drain urine (pee) from the kidneys, store it, and then release it when you pee.

Important terms

NKFI kidney health resources

The information shared on this website has been reviewed by staff at the New York City headquarters of the National Kidney Foundation. Please note: material contained here are intended solely for reference. This material does not constitute medical advice; it is intended for informational purposes only. If you feel you need professional medical care, please consult a physician for specific treatment recommendations.

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