There are five stages of chronic kidney disease (CKD), with stage 5 being kidney failure. The stages are based on your estimated glomerular filtration rate, or eGFR, a number that reflects how well your kidneys filter waste from your blood. A normal eGFR is 90 or above, and kidney failure begins when it drops below 15.
Stage 3 is split into two substages (3a and 3b), so you may sometimes see references to six categories. Each stage represents a different level of kidney function loss, and knowing where you fall helps determine what treatment you need and how aggressively to manage it.
The Five Stages and Their GFR Ranges
Stage 1 means your eGFR is 90 or higher. Your kidneys still filter at a normal rate, but there’s already evidence of damage, usually detected through protein (albumin) in your urine. A mildly reduced GFR alone, without these markers, does not count as kidney disease.
Stage 2 means your eGFR falls between 60 and 89. Kidney function is mildly decreased, and like stage 1, a diagnosis requires signs of actual kidney damage such as abnormal urine protein levels or structural changes visible on imaging. Many people with stage 1 or 2 have no symptoms at all.
Stage 3a means an eGFR of 45 to 59, representing mild to moderate loss of function. Stage 3b drops to 30 to 44 and is considered moderate to severe. This split matters because stage 3b carries a significantly higher risk of complications and progression to kidney failure. Complications like anemia, bone mineral imbalances, and acid buildup in the blood can begin appearing at stage 3b, though the risk is still relatively low. About 5.1% of U.S. adults have stage 3 kidney disease, making it the most commonly diagnosed stage.
Stage 4 means an eGFR of 15 to 29, a severe loss of kidney function. At this point, planning for dialysis or transplant evaluation typically begins. Surgeons may start preparing vascular access for dialysis when eGFR drops below 20, since the access point needs about three months to mature before it can be used.
Stage 5 means an eGFR below 15. This is kidney failure, also called end-stage renal disease (ESRD). The kidneys can no longer sustain life on their own, and most people at this stage need dialysis or a kidney transplant. Only about 0.2% of U.S. adults reach stage 5.
How eGFR Is Measured
Your eGFR is calculated from a simple blood test that measures creatinine, a waste product your muscles produce at a steady rate. The current standard formula, updated in 2021, factors in your age, sex, and creatinine level. Older formulas adjusted for race, but the newer race-free equations are now recommended. A more precise version of the test also incorporates a second blood marker called cystatin C, which can be especially useful when the creatinine-only estimate might be inaccurate, such as in people with unusually high or low muscle mass.
Doctors also measure albumin in your urine using a urine albumin-to-creatinine ratio (ACR). This result is categorized into three levels: normal (under 30 mg/g), moderately increased (30 to 300 mg/g), and severely increased (over 300 mg/g). Higher albumin levels signal more kidney damage regardless of your GFR stage, and the combination of both numbers gives the most accurate picture of your kidney health and your risk of getting worse.
What Each Stage Feels Like
Stages 1 through 3a rarely produce noticeable symptoms. Most people discover they have kidney disease through routine blood work or urine tests, not because they feel sick. This is one reason kidney disease often goes undetected for years.
By stage 3b, some people begin to notice subtle changes like fatigue or mild swelling, but many still feel fine. The complications happening inside, like shifts in calcium and phosphorus balance, are detectable through lab work before they cause obvious symptoms.
Stages 4 and 5 are where symptoms become hard to ignore. Common ones include nausea, vomiting, loss of appetite, persistent fatigue, trouble sleeping, and difficulty concentrating. Blood pressure can become very hard to control. Fluid retention may cause swelling in the legs and, if fluid reaches the lungs, shortness of breath. Potassium levels can rise dangerously high, posing a direct threat to heart function. In the final stages, kidney disease can affect the nervous system, leading to personality changes or confusion, and can cause inflammation around the heart.
How Each Stage Is Managed
In the earlier stages, the goal is to slow or stop progression. Two things make the biggest difference: keeping blood pressure at or below 130/80 and managing the underlying cause, whether that’s diabetes, high blood pressure, or another condition. A low-sodium diet (around 2,000 milligrams per day) helps with blood pressure and fluid balance. Depending on your stage, you may also need to limit potassium and phosphorus in your diet. A dietitian can tailor recommendations based on your specific kidney function and overall health.
As kidney disease advances into stage 4, the focus shifts toward preparing for the possibility that your kidneys will eventually stop working well enough on their own. Transplant evaluation generally starts when eGFR falls below 20. If a transplant isn’t an option, dialysis planning begins. Hemodialysis typically involves visiting a dialysis center three times a week for about four hours per session, though home-based options exist. Peritoneal dialysis uses fluid placed into the abdomen to filter waste and can be done during the day or overnight with a machine.
A transplanted kidney functions like a natural one, filtering blood and producing urine. Recipients take anti-rejection medications long term to prevent the immune system from attacking the new organ.
Why the Staging System Matters
Kidney disease is defined as abnormalities in kidney structure or function lasting more than three months. The staging system exists because the same disease behaves very differently at different levels of function loss. Someone at stage 2 might live decades without progressing, while someone at stage 4 may need dialysis within a few years. About 14% of U.S. adults have some form of kidney disease based on reduced GFR, elevated urine albumin, or both. The vast majority are in the earlier stages, where lifestyle changes and medical management can meaningfully change the trajectory.
Albumin levels in urine matter just as much as the GFR number. Two people with the same eGFR can have very different outlooks depending on how much protein is leaking into their urine. Higher albumin levels at any stage increase the risk of both kidney failure and heart disease. This is why the modern classification system uses a grid of GFR stage and albumin category together, rather than GFR alone, to guide treatment decisions.