What Your eGFR Number Actually Tells You

eGFR stands for estimated glomerular filtration rate, and it measures how well your kidneys are filtering waste from your blood. The number ranges from 0 to 90 and higher, and it determines which stage of kidney disease you have. Your doctor calculates it from a blood test that measures creatinine (a waste product your muscles make) and factors in your age, sex, and race. A higher eGFR is better—it means your kidneys are working well.

The five stages of chronic kidney disease are defined entirely by eGFR ranges. Stage 1 means your kidneys are working normally (eGFR 90 or higher) but you have other signs of kidney damage. Stage 5 means your kidneys are working at less than 15 percent capacity and you will need dialysis or a transplant. Most people with early-stage kidney disease have no symptoms at all, which is why the eGFR number matters: it catches the problem before you feel sick.

One eGFR test is not a diagnosis. Your doctor will order it again weeks or months later to see whether your kidney function is stable, improving, or declining. A single low number can be caused by dehydration, infection, or medication, so doctors look at the trend over time.

Key Takeaways

  • eGFR is a number from 0 to 90+ that shows what percentage of your kidney function remains, calculated from a blood creatinine test.
  • The five stages of kidney disease are based on eGFR ranges, with stage 1 being normal function and stage 5 being kidney failure.
  • Most people with early kidney disease have no symptoms, so regular blood tests are the only way to catch it.
  • Slowing kidney disease progression requires managing blood pressure and blood sugar, taking prescribed medications, and making dietary changes.
  • Your nephrologist (kidney specialist) can tell you which interventions matter most for your specific stage and cause of kidney disease.

The Five Stages and What Each eGFR Range Means

Stage 1 kidney disease means your eGFR is 90 or higher—your kidneys are filtering normally. But you have other signs of kidney damage, such as protein in your urine, blood in your urine, or imaging that shows a kidney problem. Many people stay in stage 1 for years without any change.

Stage 2 is eGFR 60 to 89. Your kidney function is mildly reduced, and you still have signs of kidney damage. Like stage 1, you may have no symptoms. At this stage, the focus is on slowing any further decline.

Stage 3a is eGFR 45 to 59, and stage 3b is eGFR 30 to 44. These are grouped together because kidney function is moderately reduced. You might start to notice symptoms such as fatigue, swelling in your hands or feet, or changes in how often you urinate. Your doctor will monitor you more closely and may refer you to a nephrologist.

Stage 4 is eGFR 15 to 29. Kidney function is severely reduced, and symptoms become more noticeable. Your doctor will begin preparing you for stage 5 by discussing dialysis or transplant options and may start you on medications to manage complications.

Stage 5 is eGFR below 15. Your kidneys are working at less than 15 percent capacity. You will need dialysis (a machine that filters your blood) or a kidney transplant to survive. Some people choose palliative care instead, focusing on comfort rather than life-extending treatment.

Why Blood Pressure and Blood Sugar Control Matter Most

High blood pressure and high blood sugar are the two biggest drivers of kidney disease progression. They damage the tiny blood vessels inside your kidneys that do the filtering work. Controlling both slows that damage significantly, even if you cannot reverse it.

For blood pressure, your target is usually lower than it is for people without kidney disease. Your doctor may aim for below 120/80 or even lower depending on your stage and how much protein is in your urine. This often means taking more than one blood pressure medication. The most commonly prescribed are ACE inhibitors and ARBs (angiotensin receptor blockers), which protect the kidneys in addition to lowering pressure.

For blood sugar, tight control slows kidney damage in people with diabetes. This means checking your blood sugar regularly if you take insulin or certain other medications, and working with your doctor or a diabetes educator to adjust your diet and medications. Even small improvements in your average blood sugar (measured by A1C tests) reduce the rate of kidney decline.

If you have both high blood pressure and diabetes, controlling both is not optional—it is the single most important thing you can do to protect your remaining kidney function.

Dietary Changes That Slow Kidney Disease

Your kidneys struggle to handle excess sodium, potassium, and phosphorus as they weaken. Reducing these does not cure kidney disease, but it can slow progression and prevent complications.

Sodium raises blood pressure and makes your kidneys work harder. Most people with kidney disease aim for less than 2,300 mg per day, though your nephrologist may recommend lower. This means limiting processed foods, canned soups, deli meats, and restaurant meals, which contain most of the sodium in a typical diet. Cooking at home and using herbs instead of salt is the most practical way to cut sodium.

Potassium builds up in your blood when your kidneys cannot filter it out, and high potassium can cause dangerous heart rhythms. In early stages (1 and 2), you may not need to restrict it. In stages 3 and beyond, your doctor may ask you to limit high-potassium foods such as bananas, oranges, potatoes, tomatoes, and spinach. A renal dietitian can tell you which foods are safe for your specific stage.

Phosphorus also builds up as kidney function declines, and it can weaken your bones and harden your blood vessels. Phosphorus is found in dairy products, nuts, seeds, and processed foods. In early stages you may not need to restrict it; in later stages your doctor may prescribe a phosphate binder medication that you take with meals.

Protein is more complicated. Your kidneys have to process protein, so eating less protein reduces their workload. But you still need enough to maintain muscle. Your doctor or a renal dietitian will tell you the right amount for your stage—usually somewhere between 0.6 and 0.8 grams per kilogram of body weight per day.

Medications That Protect Your Kidneys

Beyond blood pressure and blood sugar medications, several other drugs can slow kidney disease progression or prevent complications.

ACE inhibitors and ARBs are usually the first choice for people with kidney disease, especially those with diabetes or high blood pressure. They lower blood pressure and reduce protein leakage into the urine, both of which protect the kidneys. Common ACE inhibitors include lisinopril and enalapril. Common ARBs include losartan and valsartan. You should not take both at the same time.

SGLT2 inhibitors are a newer class of diabetes medication that also protects the kidneys. Drugs such as empagliflozin and dapagliflozin slow kidney disease progression even in people without diabetes. Your doctor may prescribe one if you have diabetes or if your kidney disease is advancing quickly.

GLP-1 receptor agonists are diabetes medications that also lower blood pressure and may slow kidney disease. They include semaglutide and dulaglutide.

Finerenone is a newer medication that reduces kidney disease progression in people with diabetes. It works differently from ACE inhibitors and can be added to your regimen.

Your nephrologist will choose medications based on your eGFR stage, the cause of your kidney disease, whether you have diabetes, and your other health conditions. Do not stop or change any kidney medication without talking to your doctor first.

When to See a Nephrologist and What to Expect

Your primary care doctor can manage early kidney disease, but a nephrologist (a doctor who specializes in kidney disease) becomes important as your eGFR declines. Most doctors refer you to a nephrologist when your eGFR drops below 30, though some refer earlier if your kidney disease is advancing quickly or if the cause is unclear.

At your first nephrologist visit, bring all your blood pressure and blood sugar records, a list of all your medications and supplements, and any imaging or biopsy results you have had. The nephrologist will review your eGFR trend, check your urine for protein, and discuss your diet and medications. They will also screen you for complications such as anemia (low red blood cells), bone disease, and heart problems.

If your eGFR is approaching stage 5, your nephrologist will discuss dialysis and transplant options with you well in advance. This gives you time to prepare emotionally and practically, and it allows time for a living kidney donor to be evaluated if that is an option you want to explore.

Lifestyle Changes Beyond Diet and Medication

Several habits slow kidney disease progression independent of medication. Staying physically active, even at a moderate level such as walking 30 minutes most days, helps control blood pressure and blood sugar and reduces inflammation. You do not need to run marathons—consistent, gentle activity is what matters.

Smoking accelerates kidney disease, so quitting is one of the highest-impact changes you can make. Smoking damages blood vessels and raises blood pressure, both of which harm your kidneys.

Limiting alcohol protects your kidneys and your overall health. Heavy drinking raises blood pressure and can damage your kidneys directly.

Sleep matters too. Poor sleep raises blood pressure and blood sugar and increases inflammation. Aiming for 7 to 9 hours per night supports kidney health along with everything else.

Managing stress through meditation, deep breathing, or activities you enjoy also helps, because chronic stress raises blood pressure and blood sugar.

Frequently Asked Questions

Can kidney disease be reversed?

No, chronic kidney disease cannot be reversed. Once kidney tissue is damaged, it does not regenerate. However, progression can be slowed or even stopped with proper management of blood pressure, blood sugar, and diet. Some people stay in the same stage for many years.

What should I avoid if I have kidney disease?

Avoid NSAIDs such as ibuprofen and naproxen, which can damage your kidneys further. Ask your doctor before taking any over-the-counter medication. Also avoid high-sodium foods, excess potassium and phosphorus depending on your stage, and herbal supplements unless your nephrologist approves them. Do not use salt substitutes without asking your doctor, because many contain potassium.

How often should I get my eGFR checked?

If you have stage 1 or 2 kidney disease, your doctor may check it once a year. In stage 3, usually twice a year. In stage 4, every three months or more often. The more advanced your disease, the more frequently you need monitoring to catch rapid changes.

Do I need to see a nephrologist if my eGFR is stable?

Not necessarily in early stages. Your primary care doctor can manage stage 1 and 2 kidney disease if your eGFR is stable and you do not have complications. But if your eGFR is declining, if you have high levels of protein in your urine, or if you develop symptoms, a nephrologist can help optimize your treatment plan.

What happens if I reach stage 5?

You will need dialysis or a kidney transplant to survive. Dialysis filters your blood artificially three times a week for several hours each session, or you can do it nightly at home. A transplant means receiving a kidney from a donor (living or deceased) and taking medications to prevent rejection. Your nephrologist will discuss both options with you and help you decide which is right for your situation.