What is eGFR ?
Your kidneys are vital organs that quietly work around the clock to remove waste and keep your body in balance. One of the most important indicators of how well your kidneys are functioning is your eGFR, or estimated glomerular filtration rate. Whether you're managing a chronic condition or simply monitoring your health, understanding your eGFR can offer early clues about kidney health, before symptoms even appear. But what exactly is eGFR, what do different values mean, and how can you improve it?
Table of Contents
- What is eGFR?
- What is a good eGFR value?
- What does a low eGFR value mean?
- Symptoms of an eGFR value that is too low
- eGFR Testing
- How can I increase my eGFR?
- Summary
What is eGFR?
eGFR stands for estimated glomerular filtration rate and reflects how well the kidneys filter blood. It is calculated based on blood creatinine levels, a waste product produced when muscles break down energy. Healthy kidneys continuously filter creatinine from the blood, removing it through urine. When kidney function declines, creatinine builds up in the blood. The eGFR result estimates how much blood the kidneys filter per minute and serves as an important indicator of kidney function (Australian Bureau of Statistics, 2025).
Why is eGFR important?
The kidneys play a vital role in removing waste products from the body through urine. When kidney function declines, waste can build up in the blood, leading to serious health issues. A low eGFR can indicate kidney damage or reduced kidney function, which may require further investigation or treatment.
Measuring eGFR is particularly important for people with risk factors such as:
- Diabetes
- High blood pressure (hypertension)
- Family history of kidney disease / Biological family history of chronic kidney disease (CKD)
- Older age (over 60)
- Use of medications that affect kidney function
- Overweight / Obesity (BMI > 25)
- Congenital conditions (present at birth) that affect kidney function
- Frequent urinary tract infections (UTIs) or urinary blockages
- Heart disease, including coronary artery disease
- Kidney transplant history
Source: National Kidney Foundation, n.d.; Cleveland Clinic, 2025
What is a good eGFR value?
The filtration rate varies from person to person. It decreases with age. Therefore, people of advanced age usually have a lower eGFR, which is not considered abnormal due to age. The approximate ranges can be found below:
| Age (years) | Average eGFR (mL/min/1.73m²) |
|---|---|
| 20–29 | 116 |
| 30–39 | 107 |
| 40–49 | 99 |
| 50–59 | 93 |
| 60–69 | 85 |
| 70+ | 75 |
Source: National Kidney Foundation, n.d.
What does a low eGFR value mean?
An eGFR value that is too low can mean that the kidneys no longer function optimally, so that the blood is not properly purified. This gives waste products the opportunity to accumulate in the body. Kidneys that no longer function optimally are often unable to properly regulate the fluid balance in the body. Furthermore, reduced kidney function can cause problems with bone health. That’s because the kidneys are less able to make vitamin D, which makes bones weaker and possibly more likely to break. People with a lowered eGFR have a higher risk of chronic kidney disease (CKD) progressing to kidney failure. The earlier that kidney disease is found, the greater the chance of slowing or stopping it from getting worse (Albert Schweitzer ziekenhuis, n.d.).
Which eGFR value is critical?
The stages of chronic kidney disease (CKD) describe how well your kidneys work based on eGFR. A lower eGFR value corresponds to different stages of kidney disease severity:
| Stage of chronic kidney disease (CKD) | eGFR result (mL/min/1.73m²) | What it means |
|---|---|---|
| Stage 1 | 90 or higher | – Mild kidney damage – Kidneys work as well as normal |
| Stage 2 | 60–89 | – Mild kidney damage – Kidneys still work well |
| Stage 3a | 45–59 | – Mild to moderate kidney damage – Kidneys don’t work as well as they should |
| Stage 3b | 30–44 | – Moderate to severe damage – Kidneys don’t work as well as they should |
| Stage 4 | 15–29 | – Severe kidney damage – Kidneys are close to not working at all |
| Stage 5 | Less than 15 | – Most severe kidney damage – Kidneys are very close to not working or have stopped working (failed) |
Source: American Kidney Fund, 2025
Symptoms of an eGFR value that is too low
The symptoms of an eGFR value that is too low are not always immediately noticeable. During mild stages when the value is only slightly lowered, there are sometimes no symptoms at all. When low eGFR has progressed to moderate or severe renal failure, the following symptoms may occur:
- Urinating more often or less often than usual
- Itching
- Feeling tired
- Swelling in your arms, legs, or feet
- Muscle cramps
- Nausea and vomiting
- Loss of appetite
Source: National Kidney Foundation, n.d.
eGFR Testing
Testing your eGFR with Homed-IQ provides insight into the filtration rate of the kidneys. This biomarker is part of the Liver and Kidney Function Test. This home test consists of a urine test and a finger prick for blood collection, after which a certified laboratory carries out the analysis. In addition to the eGFR value, this test provides insight into a number of other biomarkers, such as ALT, AST, GammaGT, Bilirubin, Albumin, Creatinine, eGFR, and Alkaline Phosphatase. With this, the test offers several parameters to determine your kidney and liver function. In the initial stages of kidney or liver disease, symptoms are not always noticeable. Therefore, testing can offer early detection.
How can I increase my eGFR?
To prevent or slow down kidney function and increase eGFR, the following tips can be followed:
- Treat high blood pressure with salt restriction and possibly medication
- Reduce protein excretion in urine with salt restriction and possibly medication
- Follow a protein-restricted diet
- Quit smoking
- Lose weight if overweight
- Avoid kidney-damaging medicines (e.g., NSAIDs)
- Use X-ray contrast cautiously
- Even with normal blood pressure: consider blood pressure–lowering drugs that protect remaining kidney filters
If eGFR is severely low, medication to support the filtration function of the kidneys in the removal of waste may also be prescribed. More severe kidney failure may require dialysis or a kidney transplant.
Source: UMCG, n.d.
Summary
eGFR is a key marker of kidney function, calculated using creatinine levels, age, and other factors. A value above 90 mL/min/1.73 m² is generally considered normal, while lower values may indicate decreased kidney performance. Causes of low eGFR include age, chronic kidney disease, diabetes, high blood pressure, and certain medications. Although early stages may show no symptoms, advanced kidney damage can lead to fatigue, fluid retention, and bone weakness. eGFR can be supported through a kidney-friendly diet, medication, and—if necessary—dialysis or transplant. With Homed-IQ’s at-home test, tracking your kidney health is simple, accessible, and informative.
