Introduction
The estimated glomerular filtration rate is the measure of the glomerular filtration rate that is used to determine kidney function. The low estimated glomerular filtration rate concludes that the kidneys are not functioning well as they should. Patients with low estimated glomerular filtration rates are at an increased risk of having kidney failure that progresses through chronic kidney disease. Early diagnosis of kidney disease is better as the chance of slowing or stopping it from getting worse is more.
How Is the Estimated Glomerular Filtration Rate Measured?
Calculating an accurate glomerular filtration level is challenging as the measured glomerular filtration rate is a complicated and lengthy process for both the physicians as well as the patients. That is why a formula is used to measure the estimated GFR (eGFR). These estimates of GFR are significant for the identification of various stages of kidney disease, which generally presents with new symptoms until the kidney function worsens to kidney failure. The standard way to calculate eGFR is with a simple blood test that measures the levels of creatinine. Creatinine is the best product that forms from the digestion of dietary protein and the normal breakdown of muscle tissue. Besides chronic kidney disease, creatinine levels are affected by other factors that include muscle mass, malnutrition, chronic illness, and diet.
Besides creatinine, a urine test is done to measure albumin, a protein in the urine also called albuminuria. Blood of protein in the urine is an early sign of kidney disease. Based on the blood and urine tests, the physician can also order some other tests that include -
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Imaging Tests - Imaging tests such as computed tomography (CT) scan or an ultrasound can be done to get a picture of the kidneys and urinary tract. This provides information to the physician on whether the kidneys are damaged, decreased, or increased in size, whether there is a presence of obstruction like a kidney stone or a tumor, and if there is a problem in the structures of the kidney and urinary tract.
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Kidney Biopsy - Kidney biopsy is a medical procedure in which a piece of the kidney is taken out and studied under a microscope to check for a specific type of kidney disease. It shows the type and amount of kidney damage and helps in treatment planning.
When Is Estimated Glomerular Filtration Rate Testing Done?
Kidney disease in the early stage does not appear with symptoms. However, the physician can recommend an eGFR test if the patient is at a high risk of developing kidney disease. Risk factors for chronic kidney disease include -
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Family history of kidney disease.
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Obesity.
The latest ages of chronic kidney disease need an estimated glomerular filtration test if the patient has the following symptoms-
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Swelling in the arms, legs, or feet.
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Nausea and vomiting.
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Loss of appetite.
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Itching.
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Feeling tired.
What Does an eGFR Test Result Conclude?
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An eGFR of 60 or higher for three months with kidney injury marked by high levels of albuminuria or an estimated glomerular filtration rate less than 60 for more than three months concludes chronic kidney disease. The nephrologist will try to find the cause of the kidney disease and continue to check the kidney function for further assessment and treatment planning.
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It is also mandatory to know that the eGFR declines with age. A low eGFR in older persons will not always mean chronic kidney disease, even if the value is less than 60.
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Based on the GFR, the stages of chronic kidney disease can be graded and kidney function can be assessed. These include-
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In stage 1 kidney disease with normal kidney function, the GFR rate is 90 or higher.
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In stage 2 kidney disease with mild loss of kidney function, the GFR rate is 89 to 60.
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In stage 3 kidney disease with mild to a severe loss of kidney function, the GFR rate is between 59 to 30.
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In stage 4 kidney disease with severe loss of kidney function, the GFR rate is between 29 to 15.
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Stage 5 kidney disease ends in kidney failure, and the GFR rate is less than 15.
How to Prevent Kidney Damage?
Kidney damage can be prevented by:
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Get the kidneys inspected at least every year. The healthcare team will do a simple blood test to measure the eGFR. They will also do a urine albumin-to-creatinine ratio (UACR), which reveals if there is a presence of protein (albumin) in the urine. Protein in the urine means that there is a presence of kidney damage.
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Control blood pressure if there is high blood pressure.
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Control blood sugar levels if there is diabetes.
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If there are chances of kidney damage, avoid non-steroidal anti-inflammatory drugs (NSAIDs) such as ibuprofen and naproxen.
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If you have chronic kidney disease, inform the doctor before having any contrast dye test.
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Exercise and follow a healthy diet low in saturated fat, sodium, and sugar but high in vegetables, fruits, whole grains, lean meats, fish, and poultry. Avoid highly processed foods.
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Try to maintain a healthy weight. Lose weight if your doctor says that you should.
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Discuss any minerals, vitamins, herbs, weight loss, or body-building supplements with your doctor before taking them. Many of these products can hurt the kidneys.
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Make sure that any drugs taken are the right dose for the age and the level of kidney function. You should discuss it with the doctor and take them.
Conclusion
The kidneys are part of the urinary system. Glomeruli are tiny filters that help remove waste from the blood. The estimated glomerular filtration rate (eGFR) measures the filtered blood every minute based on the body size. After a routine blood test, eGFR is often part of the basic metabolic panel as it helps in diagnosing kidney disease. Kidney disease arises when one or both kidneys are damaged. In the case of kidney disease, the glomeruli filter less blood. Hence, dangerous toxins can build up in the blood. Kidney disease symptoms like frequent urination do not appear in up to 40 percent of kidney function. eGFR helps in detecting the disease early so that the treatments can be started to slow or stop kidney damage.
