There are five stages of chronic kidney disease (CKD), numbered 1 through 5, with stage 1 being the mildest and stage 5 representing kidney failure. Each stage is defined by how well your kidneys filter waste from your blood, measured by a number called your estimated glomerular filtration rate, or eGFR. Technically, stage 3 is split into two substages (3a and 3b), so you may see references to six categories in total.
How eGFR Determines Your Stage
Your eGFR is calculated from a simple blood test that measures creatinine, a waste product your muscles produce at a steady rate. The formula also factors in your age and sex. The result tells you roughly how many milliliters of blood your kidneys can filter per minute. A healthy kidney filters 90 mL/min or more. As that number drops, your stage goes up.
Here are the five stages and their eGFR ranges:
- Stage 1: eGFR of 90 or above. Kidney function is normal or near-normal, but there is some sign of damage, such as protein in the urine or a structural abnormality found on imaging.
- Stage 2: eGFR of 60 to 89. A mild decrease in function, again with evidence of kidney damage. An eGFR in this range without any other sign of damage does not count as CKD.
- Stage 3a: eGFR of 45 to 59. Mild to moderate loss of function.
- Stage 3b: eGFR of 30 to 44. Moderate to severe loss of function.
- Stage 4: eGFR of 15 to 29. Severe loss of function.
- Stage 5: eGFR below 15. Kidney failure.
One important detail: stages 1 and 2 require evidence of actual kidney damage beyond the eGFR number alone. Many people naturally have an eGFR between 60 and 89 as they age, and that alone does not mean they have kidney disease. Starting at stage 3, the eGFR drop itself is enough to qualify as CKD regardless of other findings.
Why Stage 3 Is Split in Two
Stage 3 covers a wide range of kidney function, from 30 to 59 mL/min, which is why guidelines divide it into 3a and 3b. The distinction matters more than it might seem. A ten-year follow-up study found that people with stage 3b CKD had roughly three times the risk of progressing to kidney failure compared to those with stage 3a. Stage 3b patients also faced higher rates of cardiovascular problems. If your doctor tells you you’re “in stage 3,” it’s worth asking whether you’re in 3a or 3b, because the outlook and urgency of treatment differ significantly.
Why Most People Don’t Feel Symptoms Early On
Kidney disease is often called a silent condition because stages 1 through 3, and sometimes even stage 4, typically produce no obvious symptoms. Your kidneys have a large reserve capacity, so they can lose a substantial amount of function before your body shows signs of trouble. Most people are diagnosed through routine blood work rather than because they felt sick.
Symptoms generally appear only in advanced disease (late stage 4 or stage 5) and can include nausea, vomiting, loss of appetite, persistent fatigue, trouble sleeping, difficulty concentrating, shortness of breath from fluid buildup, and blood pressure that becomes increasingly hard to control. By that point, the kidneys are filtering so little waste that toxins accumulate in the bloodstream.
How Common Each Stage Is
Data from the U.S. Renal Data System, based on national health surveys from 2017 to early 2020, gives a clear picture of how many American adults fall into each category. About 65.5% of adults have an eGFR of 90 or above, and another 28.9% fall in the 60 to 89 range. Among those with diagnosed CKD, 5.1% of adults are in stage 3 (4.0% in 3a, 1.1% in 3b), 0.3% are in stage 4, and 0.2% are in stage 5. The vast majority of people with CKD, in other words, are in stage 3 or earlier.
Protein in the Urine Adds Another Layer
Your stage number is only half the picture. Doctors also check for albumin (a type of protein) in your urine, because leaking protein is an independent sign of kidney damage and a strong predictor of how quickly the disease will progress. Even someone with a normal eGFR can be at higher risk if their kidneys are spilling significant amounts of protein. When your doctor gives you a full CKD classification, it combines your eGFR stage with your level of albuminuria to estimate your overall risk of complications.
What You Can Do at Each Stage
In stages 1 and 2, the primary goal is to keep your eGFR stable and prevent further damage. Blood pressure control is the single most important step. For most people, that means keeping blood pressure below 140/90 mmHg, though your doctor may set a lower target. Certain blood pressure medications (those ending in “-pril” or “-sartan”) have a specific protective effect on the kidneys and are often prescribed even when blood pressure isn’t dramatically elevated. If you have diabetes, keeping your A1C below 7% helps protect kidney function as well.
Lifestyle measures matter across all stages: staying active for at least 30 minutes on most days, aiming for 7 to 8 hours of sleep, maintaining a healthy weight, and quitting smoking if you smoke. One practical warning worth highlighting is that common over-the-counter pain relievers like ibuprofen and naproxen can damage your kidneys and trigger acute injury, so you should avoid using them regularly once you have any stage of CKD.
In stages 3 and 4, these same strategies continue, but monitoring becomes more frequent and dietary adjustments (often developed with a dietitian) become more important. Your doctor will track your eGFR over time to gauge whether kidney function is stable or declining.
What Happens at Stage 5
Stage 5 means the kidneys can no longer sustain the body’s needs on their own. This is sometimes called end-stage kidney disease or kidney failure. At this point, the two main treatment paths are dialysis and kidney transplantation. Dialysis does the filtering work your kidneys can no longer perform, either through a machine that processes your blood or through a fluid exchange in your abdominal cavity.
Dialysis doesn’t automatically begin the moment your eGFR drops below 15. Guidelines recommend starting based on symptoms rather than a fixed number. Most people begin dialysis when their eGFR falls somewhere between 5 and 10, at which point they’re typically experiencing noticeable symptoms like severe fatigue, nausea, fluid retention, or cognitive changes that don’t respond to other treatments. Some people choose conservative management instead, focusing on comfort and quality of life without dialysis.
Planning for stage 5 ideally starts well before you reach it. If your eGFR is declining in stage 4, your care team will discuss your options so that the transition, whether to dialysis or a transplant waiting list, happens on your terms rather than as an emergency.