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. Stage 3 is further divided into two substages, 3a and 3b, so you may see the system described as having six tiers in practice.
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 factors in your age and sex to estimate how many milliliters of blood your kidneys can filter per minute. A higher number means better kidney function. The most accurate version of this test also measures a second protein called cystatin C, which helps confirm borderline results, especially when a treatment decision hinges on the exact number.
Here’s how the stages break down:
- Stage 1: eGFR of 90 or above. Normal filtering, but other signs of kidney damage are present, such as protein in the urine.
- Stage 2: eGFR of 60 to 89. Mildly reduced function.
- 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.
An eGFR alone doesn’t tell the whole story. Doctors also check how much protein is leaking into your urine using a test called the urine albumin-to-creatinine ratio (uACR). A result under 30 mg/g is normal. Between 30 and 299 mg/g is moderately increased, and 300 mg/g or higher is severely increased. Two people with the same eGFR can face very different outlooks depending on how much protein their kidneys are letting through, because higher protein levels signal more active damage.
Why Stage 3 Is Split Into Two
Stage 3 covers a wide range of kidney function, from near-normal daily life to noticeably declining health. Research published in Kidney International found that people with an eGFR below 45 (stage 3b) experience faster disease progression than those in the 45 to 59 range (stage 3a), particularly older adults. That difference matters because stage 3b patients generally benefit from earlier referral to a kidney specialist, while many people in stage 3a can be managed by their primary care doctor with routine monitoring.
What Each Stage Feels Like
One of the trickiest things about kidney disease is that it produces no symptoms for most of its course. In stages 1 and 2, you’ll almost certainly feel completely normal. Your kidneys have enough reserve capacity to keep up with your body’s demands, and the only evidence of a problem shows up on lab work.
Stage 3 is when some people start to notice changes. Fatigue, weakness, and swelling in the hands or feet are common early complaints. These symptoms happen because your kidneys are struggling to balance fluids and filter waste efficiently. Not everyone in stage 3 will feel different, though, which is why regular blood and urine tests matter more than waiting for symptoms to appear.
By stage 4, most people are symptomatic. Swelling in the hands and feet becomes more pronounced, and some people experience lower back pain. Sleep problems, nausea, and changes in how often you urinate can also develop as waste products accumulate in your blood.
Stage 5, or kidney failure, means your kidneys can no longer keep you healthy on their own. Waste buildup can cause severe nausea, itching, difficulty concentrating, and dangerous shifts in blood chemistry. At this point, you need dialysis or a kidney transplant to survive.
How Each Stage Is Managed
The primary goal across all stages is the same: slow down the loss of kidney function and protect the filtering capacity you still have. Blood pressure control is the single most important lever. High blood pressure damages the tiny blood vessels in your kidneys, accelerating the disease. For most people, the target is below 140/90 mmHg. Certain blood pressure medications can slow kidney disease progression and delay kidney failure even in people whose blood pressure is already normal.
If you have diabetes, keeping your blood sugar well controlled also protects your kidneys. The typical target is an A1C below 7 percent. In early stages, the goal is straightforward: keep your eGFR stable and keep urine protein levels from rising. Dietary changes, like reducing sodium and moderating protein intake, can help take pressure off your kidneys.
In stages 1 and 2, your primary care doctor can usually manage things with periodic lab work and lifestyle adjustments. By stage 3b or 4, a referral to a nephrologist (kidney specialist) becomes important, especially if your kidney function is declining quickly. The specialist helps plan for what comes next, whether that’s more aggressive medication management, preparation for dialysis, or evaluation for a transplant.
Stage 5 requires renal replacement therapy. Dialysis takes over the filtering job your kidneys can no longer do, either through a machine that cleans your blood (hemodialysis, typically three times a week) or through a fluid exchange in your abdomen (peritoneal dialysis, often done daily at home). A kidney transplant is the other option, and for many people it offers better long-term quality of life than staying on dialysis indefinitely.
How Fast Kidney Disease Progresses
The speed of progression varies enormously. Some people stay in stage 2 or 3a for decades without ever reaching kidney failure. Others, especially those with uncontrolled diabetes or high blood pressure, can move through stages much faster. The combination of your eGFR trend over time and your urine protein levels gives the clearest picture of where things are headed. A stable eGFR with low protein in the urine is reassuring. A dropping eGFR with rising protein levels is a signal that your treatment plan may need to change.
Because early kidney disease is silent, many people are diagnosed only after routine blood work flags an abnormal creatinine level. If you have diabetes, high blood pressure, heart disease, or a family history of kidney problems, periodic eGFR and uACR testing can catch changes early, when there’s the most room to slow things down.