Kidneys play an essential role in keeping the body healthy by filtering waste and excess fluid from the blood. One of the most important measurements used to understand kidney function is GFR. If you are wondering **What is GFR?**, it stands for Glomerular Filtration Rate, an estimate of how well the kidneys are filtering blood. GFR is commonly used by healthcare professionals to assess kidney function and identify possible signs of chronic kidney disease.
GFR estimates the amount of blood filtered by the tiny filtering units inside the kidneys, called glomeruli. Because directly measuring filtration is difficult in routine healthcare, doctors generally estimate GFR using blood creatinine levels along with factors such as age and sex.
A GFR result can help healthcare professionals understand whether kidney function is within an expected range or whether further evaluation may be needed. A single result does not always provide a complete picture of kidney health. Doctors may consider trends over time, urine tests, blood pressure, medical history, and other findings.
You may see the term eGFR, which means estimated Glomerular Filtration Rate. It is usually reported in milliliters per minute per 1.73 square meters of body surface area (mL/min/1.73 m²).
Generally, a higher eGFR indicates better filtering capacity, while a persistently reduced eGFR may indicate reduced kidney function. However, eGFR naturally varies between individuals and can change temporarily because of factors such as hydration, illness, medications, or changes in creatinine.
For this reason, an abnormal eGFR should be discussed with a qualified healthcare professional rather than interpreted in isolation.
GFR values are commonly used to categorize kidney function. In adults, an eGFR of 90 or above is generally considered in the normal or high range when there are no other signs of kidney disease.
An eGFR between 60 and 89 may indicate mildly reduced kidney function, but it does not automatically mean chronic kidney disease. Other evidence of kidney damage and the duration of the abnormality are important.
An eGFR below 60 that persists for at least three months can be associated with chronic kidney disease. Lower values may indicate more advanced loss of kidney function.
People with an eGFR below 15 may have kidney failure, although diagnosis and treatment decisions depend on the complete clinical picture.
Several conditions can affect kidney filtration. Common causes include diabetes, high blood pressure, chronic kidney disease, kidney inflammation, certain inherited kidney disorders, and other conditions that damage the kidneys.
Age can also influence eGFR. Temporary changes may occur during dehydration, acute illness, or certain medication use. Therefore, a low result should be evaluated in context rather than assumed to represent permanent kidney damage.
If your eGFR has decreased, your healthcare provider may recommend repeat blood testing, urine testing, blood pressure monitoring, imaging, or other investigations.
Protecting kidney health involves managing conditions that can damage the kidneys and maintaining healthy lifestyle habits. People should work with their healthcare professionals to control blood pressure and blood glucose when needed.
Other helpful habits may include maintaining a balanced diet, staying appropriately hydrated, exercising regularly, avoiding smoking, and using medications responsibly. People with kidney disease may require individualized limits on sodium, protein, potassium, phosphorus, or fluids.