Chronic kidney disease, or CKD, happens when the kidneys slowly lose their ability to do their job over time. The kidneys are vital organs that filter waste and extra water from the blood, help control blood pressure, make hormones, and balance important minerals in the body.
When the kidneys are damaged, waste builds up, which can lead to serious health problems. CKD doesn’t always cause symptoms in the beginning, so many people don’t realize they have it until it’s more advanced. That’s why understanding the five stages of CKD can help people catch it early and take steps to slow it down.
Doctors use a simple blood test to estimate kidney function. This is called the glomerular filtration rate, or GFR. The GFR tells how well the kidneys are filtering waste. A normal GFR is usually between 90 and 120. If the number goes down, it means the kidneys are not working as well as they should.
Stage 1 of CKD means the kidneys are still working normally (GFR 90 or higher), but there may be signs of damage such as protein in the urine or an abnormal kidney scan. People at this stage often have no symptoms. However, doctors will usually suggest managing risk factors like high blood pressure or diabetes to prevent the disease from progressing.
Stage 2 means there is a mild loss of kidney function (GFR between 60 and 89), along with other signs of kidney damage.
Again, most people still feel fine. It’s common for people in this stage to not even know they have kidney problems unless they’re being tested for another reason. Regular monitoring and healthy lifestyle choices, such as eating a low-salt diet and quitting smoking, can help slow further damage.
Stage 3 is more serious and divided into two parts: Stage 3a (GFR 45–59) and Stage 3b (GFR 30–44). At this point, people may start to feel tired, have swelling in their legs or ankles, or notice changes in urination. The risk of complications such as anemia, bone disease, and high blood pressure goes up.
According to research in the American Journal of Kidney Diseases, about 1 in 10 adults may have stage 3 CKD, and many don’t know it. Early treatment, including medications and regular lab tests, can help manage symptoms and protect kidney function.
Stage 4 means the kidneys are severely damaged (GFR between 15 and 29). This stage often comes with noticeable symptoms like fatigue, swelling, loss of appetite, and trouble concentrating. Doctors usually prepare patients for possible dialysis or a kidney transplant in the future.
According to data from the National Kidney Foundation, stage 4 patients need to be closely followed by a kidney specialist, called a nephrologist, to plan the next steps and avoid complications.
Stage 5 is kidney failure (GFR below 15). At this point, the kidneys can no longer do their job, and waste builds up in the body to dangerous levels. People with kidney failure usually need dialysis (a machine that filters the blood) or a kidney transplant to survive.
Symptoms can include shortness of breath, nausea, confusion, and severe fatigue. While this stage is serious, many people on dialysis or with a successful transplant can live for many years with good medical care.
In summary, chronic kidney disease progresses slowly and is divided into five stages based on how well the kidneys are working. Early stages often have no symptoms, which is why regular checkups are so important, especially for people with high blood pressure, diabetes, or a family history of kidney problems.
The earlier CKD is found, the more that can be done to protect the kidneys and avoid serious health issues later on. With the right care and lifestyle changes, many people with CKD can live long and healthy lives.
If you care about kidney health, please read studies about how to protect your kidneys from diabetes, and drinking coffee could help reduce risk of kidney injury.
For more information about kidney health, please see recent studies about foods that may prevent recurrence of kidney stones, and eating nuts linked to lower risk of chronic kidney disease and death.
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