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eGFR is an estimate of how well the kidneys filter blood, usually calculated from the creatinine level, age, and sex. The result helps assess kidney function, but it cannot be used as a diagnosis on its own. Proper interpretation needs to consider test trends, UACR, clinical condition, and risk factors such as hypertension, diabetes, and heart disease.

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Have you ever seen the term eGFR in your medical check-up (MCU) or blood test results and been confused about what the number means? eGFR is an estimate of how well the kidneys filter blood. Its value can help give an initial picture of kidney filtration function, but it cannot be used on its own to make a diagnosis.

So, do not jump to conclusions based only on an arrow or a “low” label on a laboratory report. Your doctor needs to read eGFR together with previous results, creatinine, urine tests, your condition at the time of the test, any medications or supplements you use, and risk factors such as hypertension and diabetes.

This article helps you understand normal eGFR values, what a low eGFR means, why results can change, and the steps you can take next. You will also learn why kidney function is linked to blood pressure and heart health.

What Is eGFR?

eGFR is the estimated glomerular filtration rate, an estimate of how well the kidneys filter blood. This value helps doctors assess the kidneys’ filtering function and track changes over time.

Inside the kidneys are microscopic filtering units called nephrons. In each nephron, the glomerulus filters the blood before the body removes waste and excess fluid through urine. eGFR results are usually reported in mL/min/1.73 m².

What Does eGFR Estimate?

Simply put, eGFR estimates the kidney filtration rate. A lower value may indicate that filtering is not working as well as expected.

However, eGFR does not describe all aspects of kidney function. The number is also not a percentage of “how much of the kidneys is still working”. Because it is an estimate, its value may differ from a directly measured GFR at the individual level.

What Is the Difference Between GFR and eGFR?

GFR is the glomerular filtration rate. It can be measured directly, known as measured GFR (mGFR), or estimated with an equation, known as eGFR.

Measuring GFR directly requires a more complex procedure. For this reason, in routine testing, laboratories more often report eGFR as a practical way to assess kidney filtration function.

Kidney eGFR and Cancer EGFR

The term eGFR in this article relates to kidney function. It is different from EGFR, or epidermal growth factor receptor, a protein that may be tested in the context of certain cancers.

Why Is eGFR Important?

eGFR is important because it helps estimate kidney filtration function and monitor changes over time. This result often appears automatically when a laboratory checks creatinine, including in an MCU and in evaluations of people with hypertension, diabetes, heart disease, or other kidney risk factors.

An eGFR value becomes more meaningful when compared with previous results. In other words, the trend of your results usually provides better information than a single number on its own.

What Can eGFR Show?

eGFR results can help:

estimate the kidneys’ filtration capacity;
track changes in filtering function over time;
assign a GFR category;
determine whether additional tests are needed;
support certain clinical decisions, including dose adjustments for some medications.

In addition, clinical guidelines combine eGFR and albuminuria categories to assess chronic kidney disease and the risk of it progressing.

What Can’t Be Determined From eGFR Alone?

eGFR alone cannot confirm:

the cause of a change in kidney function;
whether a decline is temporary or permanent;
every form of kidney damage;
a diagnosis of chronic kidney disease from a single test;
the need for dialysis or a specific therapy;
the level of urgency without looking at symptoms and other results.

Chronic kidney disease is defined by abnormalities in kidney structure or function that persist for at least three months. Therefore, your doctor needs to assess how long the change has lasted, urine tests, and the clinical context before making a diagnosis.

How Is eGFR Calculated?

Laboratories usually calculate eGFR from serum creatinine level, age, and sex. One equation used in adults is CKD-EPI 2021, which does not use a race coefficient. In certain conditions, doctors may use cystatin C together with creatinine to improve the accuracy of the estimate.

You do not need to calculate eGFR yourself. What matters more is understanding the data behind the number and why the result still has limitations.

The Role of Creatinine

Creatinine is a waste product that comes from normal muscle activity. The kidneys help remove it from the blood. That is why creatinine levels are often used as an indirect marker of filtration function.

However, creatinine is also influenced by muscle mass, physical activity, diet, medications, supplements, and your physical condition. As a result, a creatinine value that is still within the reference range may not mean the same thing for everyone.

Other Information in the Equation

In adults, the creatinine-based CKD-EPI 2021 equation uses:

serum creatinine level;
age;
sex.

The combined creatinine and cystatin C equation also includes the cystatin C level. According to the NIDDK, combining the two markers generally gives a more accurate estimate than creatinine alone, especially when the result is close to an important clinical decision threshold. However, cystatin C testing is not yet routinely available at all facilities.

The equations for children and adolescents differ from the adult equation. Therefore, results in these age groups need to be calculated and interpreted with the appropriate formula.

Why Is It Called an Estimate?

No single equation is perfect for every person and every condition. eGFR may be less representative when creatinine levels change quickly, when muscle mass is very high or very low, or when certain medical conditions are present.

For this reason, doctors look at the eGFR trend in the same person and, when possible, use a consistent laboratory method. This approach is more informative than focusing on a single number.

What Is a Normal eGFR?

In general, an eGFR of 90 mL/min/1.73 m² or higher falls into category G1, which means normal or high filtration.

However, an eGFR category is not the same as a diagnosis. A value of 60 to 89 does not automatically mean kidney disease, while a value of 90 or higher does not guarantee that the kidneys are free of problems.

Category	eGFR Value (mL/min/1.73 m²)	General Meaning	Context to Consider
G1	≥90	Normal or high	Still check for albuminuria or other markers of kidney damage.
G2	60 to 89	Mildly decreased	Does not automatically mean kidney disease without persistent markers of damage.
G3a	45 to 59	Mildly to moderately decreased	Trends, UACR, risk factors, and clinical condition need to be assessed.
G3b	30 to 44	Moderately to severely decreased	Requires medical evaluation and more focused monitoring.
G4	15 to 29	Severely decreased	Requires specific management and monitoring.
G5	<15	Kidney failure	Treatment decisions are not based on the number alone.

These categories describe the level of GFR. A diagnosis of chronic kidney disease still takes into account the cause, duration, albuminuria, and other markers of kidney damage.

Does an eGFR of 60 to 89 Mean Kidney Disease?

Not always. An eGFR of 60 to 89 only supports a diagnosis of chronic kidney disease when there are markers of kidney damage (for example, albuminuria or structural abnormalities) that persist for at least three months.

Without other markers, categories G1 and G2 may fall into a low-risk group and do not meet the criteria for chronic kidney disease.

Does an eGFR of 90 or Higher Mean the Kidneys Are Definitely Healthy?

Not necessarily. An eGFR of 90 or higher indicates relatively good filtration, but it does not rule out albuminuria, blood in the urine, or structural kidney abnormalities.

Therefore, people with diabetes, hypertension, heart disease, or other risk factors may need urine tests even when their eGFR looks good.

How Does Age Affect eGFR Interpretation?

Age is part of the eGFR calculation. Filtration values also tend to decline with age in some people.

Even so, age should not be a reason to ignore a meaningful decline, especially if the result changes quickly or is accompanied by albuminuria, hypertension, or diabetes.

Creatinine, eGFR, and UACR

Creatinine, eGFR, and UACR provide different but complementary information. Creatinine and eGFR relate to filtration, while UACR helps assess albumin leaking through the kidney filters.

Test	Sample or Data Source	What Is Assessed?	Main Limitation
Creatinine	Blood	Creatinine level as an indirect marker of filtration	Influenced by muscle mass, activity, food, medications, and supplements.
eGFR	Calculation	Estimated kidney filtration rate	Not a direct measurement and not always accurate for every individual.
UACR	Urine	Ratio of albumin to creatinine in urine	The test may need to be repeated to confirm that albuminuria is persistent.

What Does Creatinine Show?

Creatinine shows the level of a waste product in the blood. When kidney filtration declines, creatinine may rise. However, your doctor needs to look at the exact number and your body characteristics, not just a “normal” or “high” label on the report.

What Does eGFR Show?

The eGFR result combines creatinine with age and sex to produce an estimated filtration rate. As a result, eGFR usually provides more informative context than creatinine alone.

What Does UACR Show?

The urine albumin-to-creatinine ratio (UACR) measures the ratio of albumin to creatinine in the urine. Healthy kidneys usually keep albumin in the blood. When albumin in the urine increases, this can be a marker of kidney damage even if eGFR is still good.

In other words, eGFR describes filtration, while UACR helps assess albuminuria. KDIGO 2024 uses both for the classification and risk assessment of chronic kidney disease.

Why Do eGFR Results Change?

eGFR results can change because of changes in kidney function, temporary conditions, body characteristics, medications, supplements, or variation between tests. Because eGFR is an estimate based on creatinine, changes in creatinine can also change the result, even when the cause is not always kidney damage.

Your Condition at the Time of the Test

Some conditions that can affect the result or its interpretation include:

dehydration or changes in fluid intake;
vomiting or diarrhea;
fever, infection, or acute illness;
recent surgery or medical procedures;
strenuous exercise shortly before the test;
eating a large amount of meat before the test.

However, these factors should not immediately be treated as a definite explanation. A low eGFR result still needs to be evaluated, especially if the change is large or accompanied by symptoms.

Muscle Mass and Body Condition

Creatinine comes from muscle. As a result, people with very high muscle mass may have higher creatinine without a matching decline in filtration. Conversely, people with very low muscle mass may have creatinine that looks low even though their kidney function is not optimal.

In addition, body size and certain health conditions can also affect the accuracy of eGFR equations.

Medications and Supplements

Tell your doctor about all prescription medications, over-the-counter medications, pain relievers, vitamins, herbal remedies, and sports supplements. Some products can affect kidney function, creatinine levels, or how the results are interpreted.

Creatine supplements, for example, can raise blood creatinine levels and affect creatinine-based eGFR. This does not automatically mean that creatine causes kidney damage. However, your doctor needs to know about its use when reading your results. Do not stop prescribed medications or supplements without guidance from medical staff.

What Does a Low eGFR Mean?

A low eGFR means that the estimated filtration capacity of the kidneys is lower than expected. However, what it means depends on previous values, how long the change has lasted, urine results, your condition at the time of the test, and other health factors.

One Result Does Not Make a Diagnosis

A single low eGFR value can appear when you are ill or when creatinine levels have not yet stabilized. Chronic kidney disease generally requires evidence of abnormal kidney function or structure that persists for at least three months.

In the context of evaluating chronic kidney disease, the 2023 National Guidelines for Medical Services (PNPK) of the Indonesian Ministry of Health (Kemenkes) list repeat testing within 12 weeks for an eGFR below 60. However, your doctor may request testing sooner if acute kidney injury or an urgent condition is suspected.

Low eGFR, Normal Creatinine

This can happen because the creatinine reference range is general, while eGFR takes age and sex into account. The same creatinine value can produce different eGFR results in two people with different characteristics.

For this reason, your doctor looks at the exact creatinine number, result trends, muscle mass, laboratory method, and clinical condition, not just the flag.

Normal eGFR, Elevated UACR

An eGFR that looks normal does not rule out kidney damage. UACR can rise while filtration still appears good.

Even so, a single UACR result can also be affected by temporary conditions. Your doctor may ask for a repeat test to confirm that albuminuria is persistent.

Sudden and Persistent Declines

A rapid decline is different from a change that develops slowly. A sudden decline may be related to acute kidney injury, severe dehydration, infection, low blood pressure, medications, or a urinary tract blockage.

In contrast, a persistent decline points more toward a chronic process.

Steps After a Low eGFR Result

The first step after getting a low eGFR result is not looking for ways to raise the number, but understanding the change and the context of the test. The following sequence can help you prepare for a medical evaluation.

1. Compare With Previous Results

Check your earlier reports and compare:

eGFR values;
creatinine;
test dates;
the laboratory or method, if listed;
the direction of change.

The eGFR trend is usually more informative than a single result.

2. Recall Your Condition at the Time of the Test

Note whether, at the time of the test, you were:

having a fever or an infection;
vomiting or having diarrhea;
drinking less fluid than usual;
exercising strenuously;
recovering from recent surgery;
changing your diet;
starting a new medication or supplement.

This information helps your doctor assess the possible effect of temporary conditions.

3. List Your Medications and Supplements

Prepare a list that includes the name, dose, and frequency of use. Also include over-the-counter medications, pain relievers, herbal remedies, vitamins, protein supplements, and creatine.

Do not stop any medication suddenly. Your doctor needs to assess the benefits, risks, and possible adjustments on an individual basis.

4. Look at Other Test Results

See whether the report also lists:

creatinine;
UACR;
urinalysis;
blood pressure;
blood sugar or HbA1c;
electrolytes;
other relevant MCU results.

The combination of eGFR and albuminuria gives a more complete risk assessment than either one alone.

5. Discuss Repeat Testing

The timing of repeat testing is not the same for everyone. Your doctor will consider the size of the change, the possibility of an acute condition, urine results, symptoms, medications, and coexisting conditions.

The Indonesian PNPK lists repeat testing within 12 weeks for an eGFR below 60 in the evaluation of chronic kidney disease. However, testing can be done sooner if an acute problem is suspected.

6. Prepare Questions for Your Doctor

You can ask:

Is this change in my results significant?
How does this result compare with my previous tests?
Do I need a UACR test?
Could my medications or supplements affect the result?
Does my blood pressure or blood sugar need to be evaluated?
When should the test be repeated?
Do I need to see a nephrology and hypertension subspecialist?

Can eGFR Improve?

eGFR can rise again if the decline was caused by reversible factors. Examples include dehydration, acute illness, a blockage, or the effect of certain medications. However, the chance of improvement still depends on the cause and each person’s condition.

In chronic kidney disease, the main goal is usually to preserve the remaining function, control risk factors, and slow the decline, not simply to chase a particular number.

When Might the Results Change?

The next eGFR value may change after:

your body’s fluid balance has stabilized;
an infection or acute illness has been treated;
a blockage has been cleared;
medications have been reviewed;
the test conditions or testing method are different.

Even so, an improved number does not always mean the underlying cause has been resolved. Conversely, a result that has not yet improved cannot be interpreted without a medical evaluation either.

Don’t Just Chase the Numbers

The goals of an eGFR evaluation are to:

understand the cause;
monitor the trend;
preserve kidney function;
control blood pressure and blood sugar;
reduce the risk of complications;
make sure medications are used safely.

Laboratory numbers are part of your health journey, not the only target.

Be Wary of Quick-Fix Claims

No drink, herbal remedy, “detox”, or supplement can be relied on to raise eGFR quickly. In addition, drinking excessive amounts of water is not a universal solution and can be dangerous for people with heart failure or fluid balance disorders.

For this reason, do not start an extreme diet or stop your medications based on online information. Safe steps need to be tailored to the cause and your physical condition.

Who Should Have an eGFR Test?

An eGFR test is especially relevant for people with kidney risk factors or conditions that require monitoring of kidney function. How often the test is needed is not the same for everyone and should be based on previous results and your doctor’s recommendation.

People With Hypertension

High blood pressure can damage the small blood vessels in the kidneys. Conversely, kidney problems can make blood pressure harder to control.

For this reason, a hypertension evaluation often includes blood and urine tests.

People With Diabetes

Long-term high blood sugar can damage the blood vessels and the filtering system of the kidneys. That is why eGFR and UACR are an important part of diabetes monitoring.

Read also:

People With Cardiovascular Risk

Heart disease, heart failure, blood vessel disorders, hypertension, and diabetes can be linked to kidney function. In addition, kidney function can influence the choice of medications and certain clinical decisions.

People With a Family History

A family history of kidney disease, kidney failure, hypertension, or diabetes can be a reason to discuss testing with your doctor.

Young People With Risk Factors

Kidney problems can also occur at a young age. However, not every young person needs to be tested at the same frequency.

Testing is more relevant when there is hypertension, diabetes, obesity or a metabolic disorder, a family history, heart disease, use of certain medications, or a previous abnormal finding. The Indonesian PNPK recommends a risk-based screening approach.

The Link Between eGFR and the Heart

eGFR is not a heart test, but kidney function is an important part of cardiovascular health. The kidneys help regulate fluids, electrolytes, and blood pressure. For this reason, heart, kidney, and metabolic conditions often need to be evaluated together.

The Kidneys Regulate Fluids

The kidneys regulate how much sodium and fluid the body keeps or removes. When this process is disrupted, fluid can build up and blood pressure can become harder to control.

In people with heart disease, changes in fluid and kidney function can affect symptoms, the use of medications, and the care plan.

Hypertension Affects the Kidneys and the Heart

Hypertension can damage the blood vessels of the kidneys while also increasing the heart’s workload. Conversely, kidney problems can help sustain high blood pressure through changes in fluid balance and hormonal systems.

However, this link does not mean that everyone with a low eGFR will definitely have heart disease. Both need to be assessed within a broader picture of health.

Diabetes as a Shared Risk Factor

Diabetes increases the risk of kidney problems and cardiovascular disease. High blood sugar, hypertension, excess body weight, and blood fat disorders also often occur together and affect more than one organ.

When Is a Heart Evaluation Relevant?

A cardiovascular evaluation becomes more relevant when changes in eGFR occur together with:

hypertension;
diabetes;
known heart disease;
shortness of breath or swelling;
fluid balance disorders;
evaluation before or after a heart procedure.

The 2026 AHA/ACC/ADA/ASN guideline emphasizes that cardiovascular, kidney, and metabolic risks are interrelated conditions that require a multidisciplinary approach.

Caring for Your Kidneys and Heart

Caring for your kidneys and heart focuses on controlling blood pressure, blood sugar, and lifestyle, as well as using medications safely. No single food or habit can ensure that kidney function stays normal.

Monitor Blood Pressure and Blood Sugar

Hypertension and diabetes are major risk factors for kidney disease. If you have either of them, follow the targets and check-up schedule given by your doctor. Do not use someone else’s targets, because each patient’s needs can differ.

Follow a Balanced Diet

Choose fresh foods and limit highly processed foods, excess salt, added sugar, and saturated fat. However, do not start restricting protein, potassium, or phosphorus without guidance from your doctor or a nutritionist.

People who already have kidney problems may need a specific dietary plan based on their laboratory results and the stage of the disease.

Drink Enough Fluids

Drink according to your body’s needs and your health condition. Fluid needs are influenced by the weather, activity, illness, and medications.

On the other hand, people with heart failure or certain kidney diseases may need to restrict their fluid intake. So, the advice to “drink as much as possible” does not apply to everyone.

Stay Active

Regular physical activity, a healthy body weight, enough sleep, and not smoking help maintain blood vessel and metabolic health.

Choose activities that suit your abilities, especially if you have heart disease or a chronic condition.

Use Medications Safely

Take medications as prescribed. Also tell your doctor about any over-the-counter medications, pain relievers, herbal remedies, and supplements you use.

Some medications need to be adjusted according to kidney function. Using certain products without supervision can also add to the risk.

Get Tested Based on Your Risk

The right testing does not mean doing every test as often as possible. Discuss your needs based on your blood pressure, blood sugar, family history, heart disease, medications, symptoms, and previous results.

When Do You Need Medical Attention?

The eGFR number alone does not determine urgency. However, certain changes in results and accompanying symptoms should not be ignored.

Results You Should Discuss With a Doctor

Talk to your doctor about your results if:

your eGFR has dropped compared with a previous test;
an eGFR below 60 is found or confirmed;
your UACR is elevated or there is blood in your urine;
your creatinine has risen;
your blood pressure is hard to control;
you have diabetes or heart disease;
the change occurred after an illness, surgery, or starting a new medication;
you do not yet understand what the results mean and what to do next.

The doctor who ordered the test or an internal medicine specialist can be a starting point. The Indonesian PNPK lists an eGFR below 60 mL/min/1.73 m² as one of the criteria for consulting a nephrology and hypertension subspecialist. A referral should also be considered if there is severe albuminuria, blood in the urine, a rapid decline in function, or another clinical condition that requires specialized care.

Understand the Numbers and Their Context

eGFR is an estimate of the kidneys’ filtering function, not a stand-alone diagnosis. Its value becomes more meaningful when read together with previous results, creatinine, UACR, blood pressure, blood sugar, medications or supplements, and your condition at the time of the test.

A low value deserves attention, but you do not need to immediately conclude that the kidney damage is permanent. Conversely, a result that looks normal is not a reason to ignore risk factors.

Ultimately, a complete understanding will help you be better prepared to talk with your doctor. The next step may be monitoring, additional tests, managing risk factors, or a kidney and heart health evaluation tailored to your needs.

Keep your medical check-up results as a baseline for future monitoring. If there are changes in your blood pressure, blood sugar, lipid profile, kidney function, ECG, ability to carry out activities, or complaints that may be related to the heart, a consultation can help determine the steps that are truly relevant.

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Reviewer

Translated from the Indonesian edition medically reviewed by Dr. dr. Faris Basalamah, Sp.JP(K), Cardiology and Vascular Medicine on July 28, 2026.

Sources as cited in the Indonesian edition.

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