Education
What are the kidneys?
The kidneys are two of the most hard-working organs in the body. Learn more about their function and how they keep the body balanced and healthy.
The kidneys are two of the most hard-working organs in the body! Their main job is to make urine by getting rid of wastes and extra water from your blood. The kidneys ensure that the body has the right balance of important minerals circulating in the blood, such as sodium, potassium, phosphorus, and calcium.
They also release hormones that regulate blood pressure and make red blood cells. They are located beneath your ribs, one on each side of your spine, behind your belly. Each kidney is the size of a closed fist and is the shape of a kidney bean.
The Kidneys at Work – How the Kidneys Work
How the kidneys filter the blood to keep the important nutrients to keep the body healthy, and turn the waste the body doesn't need into urine.
The renal artery delivers unfiltered blood to your kidneys.
Inside each kidney are one million tiny filtering units called nephrons. Each nephron has a filtering system called the glomerulus which strains the blood to clean it. The nephrom makes sure that the kidneys hold on to the nutrients and blood cells that your body needs and gets rid of waste products that it doesn’t need.
The cleaned blood is then sent back to the body, while the waste and excess fluids that were strained from the kidneys are then converted into urine (pee) which is sent to the bladder through a tube called the ureter.
Healthy Function – Kidneys and the Body
The kidneys play an important role in keeping your body healthy, and balanced.
Healthy kidneys filter the blood and send cleaned blood back to the body to support the body’s overall health.
What is CKD?
Kidney damage can happen slowly without any symptoms. Therefore, it is important for you to talk to your doctor about your kidney health, and get tested if you are at risk.
When a person is diagnosed with Chronic Kidney Disease, often referred to as CKD, it means that their kidneys are damaged and cannot filter the blood properly, leading to a build-up of wastes and toxins in the body that healthy kidneys normally remove. This damage can happen slowly over a long period of time without any symptoms appearing, which means that many people do not realize they have kidney damage until the later stages of the disease when it is difficult to make changes to stop or slow down the damage.
Therefore, it is very important for you to talk to you healthcare provider about your kidney health, ask them if you are at risk of kidney disease, and if you are, to get tested for kidney disease. If you would like to know about whether you are at risk of kidney disease, click here to take our kidney risk survey.
Testing for CKD
It is very important to get tested for CKD if you are at risk. Two simple tests - a urine test and a blood test, can be done by your doctor to provide you with an understanding of your kidney function.
There are two simple tests that are used to diagnose CKD that your doctor can request you to do at a laboratory – a blood test and a urine test. If you are at risk of kidney damage due to a condition such as diabetes or high blood pressure, your doctor should order a uACR and an eGFR test at least once per year. If you are not aware of, or do not have a risk factor for kidney disease, talk to your doctor if testing is right for you.
1. uACR test: The uACR test – also called the “urine albumin-to-creatinine-ratio” – is a urine test to measure the amount of a type of protein called albumin in your pee.
What is albumin and why is it important?
Albumin is a protein normally found in the blood. Healthy kidneys hold on to albumin, keeping it in the blood, and allow little or no albumin to appear in the pee. However, when significant amounts of albumin are found in the pee, this tells us that you may have kidney damage.
A uACR test measures the amount of albumin in your pee, and gives your doctor a snapshot of your kidneys' overall health on the day you provide your urine sample. If your levels of albumin are higher than normal, your doctor will want to test you a few more times over the following months to confirm your results. If your albumin levels remain the same or worsen over time you may have kidney damage. If you are found to have kidney damage, your doctor will want to continue to track your uACR measurements to track the progression of your kidney disease.
2. eGFR blood test: Your doctor may order a blood test to test the amount of creatinine in your blood. Once your doctor receives your results, they will use the test result to estimate your glomerular filtration rate (eGFR), a value that shows the rough percentage of kidney function that you have. eGFR is calculated using a mathematical equation that takes into consideration the amount of creatinine in your blood, as well as your age and sex. If your eGFR is less than 60, you might have CKD.
What is creatinine and why is it a concern when levels are above normal?
Creatinine is a waste product created by muscles during everyday activities. Although it is normal to have some creatinine in the blood, healthy kidneys keep levels balanced by filtering out the excess from the blood into the pee. A blood test will tell your doctor how much creatinine remains in your blood after your kidneys try to remove it. Too much creatinine in the blood can suggest that the kidneys are not filtering out the creatinine and leaving it in the blood.
Are both uACR and eGFR needed to test my kidneys?
UACR and eGFR tell us about different aspects of kidney function. In most cases both tests are needed in order to fully assess your kidney risk.
Stages of CKD
There are 5 stages of CKD ranging from normal function, down to kidney failure. Learn more about the symtoms and characteristics linked with each stage.
Normal to High Kidney Function (insert percent here) – At this stage, kidney function is normal (unless there are other markers of kidney disease). The kidneys are working well, and are filtering a healthy amount of blood.
Mild Decrease in Kidney Function – At this stage, you probably won't feel symptoms. However, to prevent your kidney function from worsening, you should be improving your lifestyle habits by eating healthy foods, participating in physical activities, and keeping your blood pressure under control.
Mild to Moderate Kidney Function – When the eGFR is less than 60 for more than 3 months, kidney damage is considered to be chronic. You may not have any symptoms or any obvious ones, however, healthy habits and medications can help prevent your CKD from progressing.
Mild to Moderate Kidney Function – At this stage, it is becoming increasingly likely that you may be experiencing some symptoms related to CKD (LINK TO SYMPTOM SECTION).
Severe Kidney Damage – At this stage, it is important to begin seeing a specialized doctor for the kidneys, called a nephrologist, and to follow recommendations for lifestyle behaviors and medications. Symptoms are likely becoming more obvious, and there may be other medical complications because of your decreased kidney function.
Approaching Kidney Failure – As the kidneys approach kidney failure, you should be having discussions with your nephrologist and care team about treatment options, including dialysis and/or kidney transplant. When the kidneys fail, and without such treatment, your life expectancy will be in the range of a few months at the most.
Common Causes of CKD
Diabetes, high blood pressure, and genetics are the three leading causes of Chonic Kidney Disease. Learn more about the causes that drive the presence of CKD.
1. Diabetes
Diabetes is the leading cause of CKD, contributing to 45% of all cases of CKD. In people with diabetes, constant spikes in blood sugar can damage the blood vessels and filtering mechanisms in the kidneys, causing them to become narrow and clogged. This damage leads to poor circulation of the blood in the kidneys, and makes it more difficult for the kidneys to filter waste out of the blood, leading to a buildup of waste. If blood sugar is not well controlled, this damage caused to the kidneys will get worse over time, causing CKD to progress.
2. High blood pressure (also known as hypertension)
High blood pressure is the second leading cause of CKD – 25% of CKD cases are caused by high blood pressure. High blood pressure causes damage to the blood vessels throughout the body, including to the vessels in the kidneys that filter the blood. This causes the kidneys to stop removing wastes and extra fluid from the blood.
High blood pressure can also be a complication of CKD. If the kidneys aren’t working well and are not able to remove excess water and waste from the blood, this can cause an increase in blood pressure, even in people who had no history of high blood pressure before they were diagnosed.
Risk Factors
There are a number of factors that can increase your risk of developing CKD. Learn more about what you can start doing today to decrease your risk.
Symptoms
If you are at high risk of developing CKD, it is important to monitor for symptoms, and talk to your doctor about getting tested.
In the early stages of CKD, symptoms may not be obvious because the body is able to deal with the reduced kidney function. Chronic kidney disease (CKD) is a silent, progressive condition that affects approximately 37 million adults in the U.S. Alarmingly, most people living with CKD are unaware they have it. That’s because early-stage CKD often presents no symptoms—by the time symptoms appear, kidney damage may already be significant.
As the disease progresses (CKD stage 3B and onward), symptoms may start to appear, or they may not appear until the later stages of diseases when there is a lot of damage done. At this point, often there are few preventative treatments available.
Additionally, many of the symptoms can suggest other illnesses, and therefore, CKD may not always be suspected. Therefore, testing for CKD through blood and urine tests, is the most reliable method for detecting kidney disease early. Early testing and diagnosis of kidney disease is important, allowing more time for treatments to slow the disease.
If you’re at high risk for CKD due to diabetes, high blood pressure, heart disease, family history, or being over the age of 60, it’s important to monitor for early warning signs and talk to your healthcare provider about getting tested.
Why Symptoms May Not Appear Right Away
In the early stages of CKD (Stages 1 to 3A), your body can often compensate for reduced kidney function. Symptoms may not appear until Stage 3B or later, when kidney function has declined enough to disrupt other systems in your body. Even then, CKD symptoms are often vague or resemble other health issues, making diagnosis difficult without proper testing.
Common symptoms of CKD to look out for are:
No Symptoms – CKD is often a silent disease, and you may not notice symptoms until kidney function is gone. Many people with CKD experience no symptoms until the disease has significantly progressed. This is why routine screening is so important for high-risk individuals.
Symptoms that may start in CKD Stage 3
Fatigue and no energy – Feeling tired or having less energy is common in CKD, and can be caused by number of different factors, such as low iron, low red blood cell count, a build-up of toxins, medications, sleep disturbances, or depression
Loss of appetite -There are a variety of factors that can contribute to a poor appetite, including: Constipation; Depression; Nausea & vomiting; Taste disturbances; Medications
Dry and Itchy Skin - As kidney function declines, there is an increased build-up of wastes in the bloodstream that can cause the skin to feel itchy
Symptoms that are more common in advanced CKD (Stages 4 or 5)
Shortness of Breath - Fluid buildup in the lungs and anemia can make it harder to breathe, especially during physical activity.
Swelling in the Feet and Ankles - Impaired kidney function can lead to sodium retention, which causes swelling in the lower extremities.
Puffiness Around the Eyes - Increased fluid retention and protein loss in the urine may result in noticeable swelling around the eyes.
Nausea and Vomiting - Waste buildup in the bloodstream (uremia), medication side effects, and digestive disturbances can all contribute to nausea, particularly in later stages.
Taste Changes or Bad Breath - A metallic taste in the mouth and persistent bad breath are signs of advanced CKD due to uremia.
Muscle Cramps - Electrolyte imbalances, particularly in calcium and phosphorus levels, may cause painful muscle cramps.
Difficulty Sleeping - Itching, restless legs, depression, and pain can all make it difficult to sleep in more advanced stages of CKD.
Changes in Urination - You may urinate more or less frequently. Foamy or bubbly urine can indicate the presence of protein, while blood in the urine should always be evaluated by a doctor.
Chest Pain - Fluid buildup around the heart or inflammation of the heart lining can cause chest discomfort in advanced cases. This should be treated as a medical emergency.
What to Do if You Notice These Symptoms
If you are experiencing any of the above symptoms—especially if you have a known risk factor—it’s important to speak with your healthcare provider. Testing your kidney function early through eGFR and uACR can lead to timely treatment and improved outcomes.
Early detection matters. The sooner CKD is diagnosed, the more opportunities there are to protect your kidneys and your overall health.
Appointments with your kidney care team
Learn more about the many different types of specialized care professionarls who provide care to people living with kidney disease.
In the early stages of CKD, regular check-ups with your family doctor (primary care provider) are important to help maintain kidney health. If the disease advances, your family doctor will refer you to a kidney health clinic for more specialized care.
Who is part of the kidney care team?
1. Family doctor (Primary care provider)
Having regular check-ups with your family doctor is important for monitoring the health of your kidneys, as well as for helping you manage your CKD symptoms or any other chronic condition you may have. If you suspect you may be at risk of CKD, having a conversation about testing with your family doctor is an important first step.
2. Nephrologist (Kidney doctor)
Nephrologists are doctors who specialize in kidney health. If you have CKD, you may be referred to a kidney doctor who will monitor your kidney health over time, discuss treatment options, and work with you and the rest of the care team to develop a plan for managing your CKD and your symptoms.
3. CKD Nurses
The nurses on your care team will help answer any questions or concerns at each stage of your CKD, and will work with the other members of the team to resolve any issues or problems that you might have.
4. Pharmacist
If you have CKD, it is important to let your community pharmacists know, since some medications may not be safe for your kidneys. Make sure to tell them about any prescription or non-prescription medications - such as vitamins and herbal supplements - you are taking. Always check with your pharmacist when you are starting a new medication; they will be able to talk with you about the proper use and potential side effects. Your kidney health team will also usually include a pharmacist.
5. Dietitian
Having a healthy diet is important for maintaining good kidney health. However, as CKD progresses through the stages, dietary recommendations may change. The kidney health dietitian on your team will provide you with dietary information tailored to your CKD stage and your specific needs.
6. Social worker
Understanding how to adjust to the different ways CKD can impact your life can be difficult. Kidney health social workers can provide you and your family members with supports and community resources to help you cope with the changes that might be happening in your life because of your CKD diagnosis – at home, at work, or in your social life.
7. Other care team specialists
If you have other chronic conditions, there might be a range of other specialized care providers you may see, such as a cardiologist (a doctor who treats heart and blood vessel diseases), or an endocrinologist (a doctor who specializes in treating diseases of the endocrine system, which is the part of the body that regulates hormones -- Diabetes is one example of a common disease that this type of doctor treats). It is very important that you make time to attend appointments with each member of your care team.
What to expect during your appointments with your nephrologist and kidney health team?
Before your appointments, you doctor will likely ask you to have a blood and urine test done so they can monitor your kidney health, as well as monitor other levels in the blood and urine related to your kidneys and overall health. These tests will need to be repeated often, so your doctor can monitor your health over time to see if there are any changes.
Make sure to come prepared to your appointments with a list of concerns and questions you may have about your kidney health. Below is an initial list of common questions to ask your family doctor or your kidney health team.
What is my level of kidney function?
Do I have CKD? What stage of CKD?
What caused my CKD?
Are my children or relatives at risk of CKD?
Is my CKD going to get worse and how will I know?
What can I do to prevent my CKD from getting worse?
What is my target blood pressure?
Is my diabetes under control?
What is my ideal body weight?
Kidney Failure Treatments
Learn more about the various treatment types, including dialysis and transplantation, that are available for people with kidney failure.
Medications
In the early stages of CKD, there are medications that are used to slow down the damage happening to the kidneys. Many of these medications are also used to treat other common diseases in CKD.
There are also a number of medications that should be avoided by people who have CKD, because they can cause kidney damage and speed up progression of the disease.
Always talk to your doctor or pharmacist before starting new medications – even medications that do not require a prescription, such as herbal supplements or vitamins.
Kidney Failure
Once 85-90% of kidney function is lost (CKD Stage 5), individuals will need to begin receiving life-saving treatment for their kidney disease because the kidneys are having a very difficult time removing waste and water from the body, leading to a build-up of toxins in the body. At this stage, the kidneys cannot recover function, and individuals need to either undergo dialysis for the remainder of their life, or undergo a kidney transplant if they are a candidate.
What is dialysis?
Dialysis is a treatment that acts like healthy kidneys and filters the blood for the body, removing waste and extra water, and keeping the nutrients in the blood balanced. There are two different types of dialysis:
1. Hemodialysis is a treatment where the blood flows continuously from the body through a special machine that helps clean the blood by removing wastes and extra water. Usually hemodialysis is done in a hospital (called in-center hemodialysis) 3 days a week for 4 hours each session (12 hours/week total). However, some kidney clinics also offer home hemodialysis, where patients receive training and equipment to allow them to conduct the treatments at home.
2. Peritoneal Dialysis is a type of treatment done at home, either during the day while the person does their normal activities, or during the night. A plastic tube (called a catheter) is inserted into the abdomen by a surgeon. During treatment, the catheter connects to a bag of fluid which flows into the body, and “pulls” extra water and waste from the blood into the abdominal area, and gets drained out of the body through the catheter.
What is a kidney transplant?
A kidney transplant is a surgery where a healthy kidney is taken from a donor and placed inside the body of someone who has CKD. Individuals are usually referred to a transplant center by their kidney doctor, where they receive a full medical and psychosocial evaluation to see if they are a candidate. The donor kidney can come from a family member or friend who is a “match”, meaning that they are suitable to undergo surgery, and that their kidney is healthy and the correct blood type. Individuals who donate a kidney can live a healthy life with their remaining kidney. After surgery, people who receive a kidney transplant will need to take mediations for the rest of their life so the body does not reject the new kidney. For some people, transplanted kidneys stop working after a few years, and they might need to go on dialysis or receive another kidney transplant. The lifespan of a transplant kidney is different person-to-person.
CKD and exercise
Engaging in routine physical activity is key for maintaining good heaalth. For people living with CKD, physical activity can help manage symptoms and slow down loss of kidney function.
Physical activity is important for keeping your body and mind healthy, and can slow down the loss of kidney function and manage symptoms. Routine physical activity can boost your energy, help you sleep better, improve your mental health, and strengthen your muscles. Exercise can also help lower blood pressure and cholesterol levels, lowering the risk of stroke and heart disease.
The level of activity required for people with CKD depends on overall health, age and physical capabilities. For people who are new to exercise, they should start slowly and gradually build-up daily activity levels. To get started with exercise, even simple activities, such as walking or gardening can help improve physical well-being. The important thing is to routinely do an amount of activity that is enjoyable and is well suitable to your lifestyle and health condition. Even though it may get more difficult to exercise as kidney function declines, it is important to stay active. However, talk with your family doctor to make sure there is nothing stopping you from exercising safely, such as any health conditions you may have.
Food and Diet
Eating a healthy diet is important for keeping the body and the kidneys healthy. Following the guidelines recommended for each stage of CKD is important to help slow down the progression of the disease.
For people who are at risk of developing CKD, eating a healthy diet according to the recommendations outlined in the Dietary Guidelines for Americans is important for maintaining healthy kidneys and a healthy body. Check out https://www.myplate.gov/ to learn more about how to eat a balanced diet for good health and well-being overall.
The National Kidney Foundation has a website covering the basics of nutrition in CKD, along with kidney-friendly recipes.
In the early stages of CKD and as the disease progresses, more specific recommendations will emerge tailored to the stage of CKD, as well as to the other health conditions a person may have. Kidney dietitians are important members of the care team who provide nutritional advice to help patients navigate CKD dietary guidelines and help manage the diseases.
Sexuality
Many aspects of CKD, such as low energy levels, depression, medications, and other co-existing medical problems may affect sexual relations for people who have CKD and their partners. Talk with your health care team for treatment and resources, and try to share how you feel with your partner.
Fertility
Although CKD can affect fertility, women in any stage of CKD can get pregnant, and therefore, it is important to use contraception.
If you have CKD and are planning on getting pregnant, it is important to discuss your health with your family doctor or nephrologist. Certain medications might be harmful to the baby, and may need to be changed or stopped. Pregnancy can also affect kidney function, so pregnant women may need heightened monitoring of their kidney function throughout their pregnancy.
Coping and Support
People living with CKD face a number of challenges related to their diagnosis. Here are some online resources that may help with the adjustment to living life with CKD.
People living with CKD face a number of challenges related to learning how to cope with the disease in their personal, family, work, financial, and social lives. The National Kidney Foundation offers a number of local and national resources, including a free helpline, peer mentoring, and online communities: https://www.kidney.org/treatment-support.