eGFR
Understanding eGFR
What is eGFR?
The estimated glomerular filtration rate (eGFR) test estimates how efficiently the kidneys are filtering waste products from the blood. It is calculated using a formula that factors in an individual's age, gender, and serum creatinine levels to assess kidney function. This test is conducted for individuals aged 18 years and above.
The estimated glomerular filtration rate (eGFR) is a measurement used to assess the efficiency of the kidneys in filtering waste and excess fluids from the blood. This test is essential for diagnosing kidney diseases, monitoring their progression, and determining treatment strategies.
eGFR is calculated using a formula that takes into account several factors, including the levels of creatinine in the blood, age, gender, and sometimes race. All these factors such as age, gender, and sometimes race are clubbed into a mathematical formula to estimate your eGFR. This calculation gives an estimate of the amount of blood filtered by the glomeruli (tiny filters in the kidneys) each minute. A lower eGFR indicates decreased kidney function, which may be a sign of kidney disease or other health issues.
The eGFR test is usually performed with kidney function test (KFT) or with serum creatinine test to give a more comprehensive assessment of kidney function. This test is often performed when individuals experience symptoms of kidney dysfunction such as urinary changes, swelling in the feet, loss of appetite, and fatigue. It is also routinely performed as part of health screenings for individuals at risk (individuals with high blood pressure or diabetes) or as a follow-up in those already diagnosed with kidney conditions. It helps doctors to stage the level of kidney disease and decide on the appropriate management or treatment.
Usually, no special preparation is needed before undergoing the eGFR test. But, it is still advised to follow your doctor's instructions closely. Additionally, it is important to provide a few details such as your age, gender, etc., at the time of sample collection as this test is conducted for individuals aged 18 years or more.
Test result ranges are approximate and may differ slightly between labs depending on the methodology and reference interval. Talk to your doctor about your specific test results. The results will help them evaluate your medical condition and formulate an overall treatment plan.
What is eGFR used for?
The eGFR test is done:
- As part of routine health checkup in conjunction with kidney function test.
- To evaluate kidney function and detect any disease or disorder of the kidneys.
- If you have risk factors like obesity, diabetes, high blood pressure, or a family history of kidney disease.
- To monitor treatment response for kidney disease.
- To determine drug dosages and monitor potential kidney toxicity that may be caused by certain medications.
- To evaluate baseline kidney function before surgeries or medical procedures.
What does eGFR measure?
The estimated glomerular filtration rate (eGFR) test is a critical measurement used to assess kidney function by estimating the rate at which blood is filtered through the glomeruli, the tiny structures in the kidneys responsible for filtering waste products and excess fluids from the bloodstream. It provides a numerical value that indicates how effectively the kidneys are performing this essential filtration process. A normal eGFR suggests healthy kidney function, while a lower eGFR may indicate reduced kidney function, which can be indicative of various conditions such as chronic kidney disease (CKD), diabetes-related kidney damage (diabetic nephropathy), hypertension-related kidney damage, or other kidney disorders. eGFR is typically calculated using a formula that takes into account factors such as age, gender, race, and serum creatinine levels—a waste product from muscle activity that the kidneys remove from the blood. Doctors use eGFR results to diagnose kidney disease, assess its severity, monitor progression over time, and determine appropriate treatment strategies to manage and potentially slow the decline in kidney function. Regular monitoring of eGFR is crucial for individuals at risk of kidney disease or those with pre-existing conditions to ensure early detection and timely intervention, thereby optimizing kidney health and overall well-being.
References
- Glomerular Filtration Rate (GFR) [Internet]. USA: NIDDK; Apr.2021 [Accessed 24 Jul. 2024]. Available from: https://www.niddk.nih.gov/health-information/professionals/clinical-tools-patient-management/kidney-disease/laboratory-evaluation/glomerular-filtration-rate
- Kaufman DP, Basit H, Knohl SJ. Physiology, Glomerular Filtration Rate. [Updated 2023 Jul 17]. In: StatPearls [Internet]. Treasure Island (FL): StatPearls Publishing; 2024 Jan-. Available from: https://www.ncbi.nlm.nih.gov/books/NBK500032/
- Vaidya SR, Aeddula NR. Chronic Kidney Disease. [Updated 2022 Oct 24]. In: StatPearls [Internet]. Treasure Island (FL): StatPearls Publishing; 2024 Jan-. Available from: https://www.ncbi.nlm.nih.gov/books/NBK535404/
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