What Is eGFR Blood Test?

Submitted on March 27, 2012

A blood test for eGFR or estimated glomuler filtration rate is a measurement used to check for the stage of renal failure that a person is experiencing. This is a test that is quite complicated and requires a trained nephrologist to perform. Blood tests for eGFR require a creatine clearance test to be performed first to ascertain the level of creatinine that is filtered out of the urine. This value is then applied to a formula and other metrics are applied before a final figure is arrived at. Despite its complexity and dependencies, it therefore measures the level of kidney disease that one is suffering from.


An eGFR blood test is used whenever there is suspicion of a kidney disease. This is usually the case in patients who are suffering from diabetes or from hypertension for a prolonged period of time. Both of these diseases affect the kidneys in different ways and overwork the kidneys to the point at which they are no longer able to function optimally anymore. The first signs of problems are when a urine test will show a high level of proteinuria and albuminuria. Once sugar is detected in the urine, this is a sure sign that the kidneys have started to get affected with diabetes.

Test Results

The test results from an eGFR test can be a bit complicated to understand but on the whole, a GFR of ninety or more is a sign of normalcy but if accompanied by albuminuria, is an indication of impending kidney, if not the case already. Between sixty- eighty nine would be the eGFR of a person with a second stage kidney disease. Any further increase in GFR counts successively gives similar indications.

Why Is It Recommended?

An eGFR blood test maybe recommended by your doctor to determine the creatinine levels in the blood. The test reveals kidney function and indicates how well or poorly your kidneys are filtering the creatinine (waste produced through muscle function) from your blood. EGFR stands for estimated glomerular filtration rate. Individuals who show symptoms of kidney malfunction need an eGFR blood test. Your doctor may use an eGFR blood test calculator that includes your creatinine test, age, sex, and race to calculate whether you fall in the high eGFR blood test bracket or low eGFR blood test.

High and Low EGFR Blood Test Range

An eGFR blood test that ranges between 60 and 90 indicates healthy kidney function. However, if the eGFR blood test range is below 60, it reveals the possibility of a kidney disease. In fact, if your report shows a low eGFR blood test in the range of 60 to 20, you should seek medical help immediately for kidney malfunction or kidney disorders. If your eGFR reflects a number below 20, you are at a risk of kidney failure. To further ascertain your kidney's health, your doctor may recommend a retake of the eGFR blood test. Along with this test, your doctor may also prescribe other tests such as urine tests (to identify proteins or blood in the urine), blood tests, and blood pressure checks, and in case of diabetes patients, blood sugar tests. Since the eGFR blood test calculator works to indicate decreased renal function, the eGFR blood test range below 60 ml/min is considered abnormal. The norm for eGFR blood test range may fall between 60ml/min to 90 ml/min. Any reading above 90ml/min may indicate high eGFR blood test and must be checked by a doctor immediately.

While the eGFR blood test is a good indicator of your kidney health, your doctor may not recommend the test if you are pregnant, younger than 18 years old, obese or overweight, and if you are of muscular build. Since the eGFR considers muscle mass while calculating the range, individuals who are 75 or older may not be included in this test due to muscle wastage caused by aging. Similarly, an overweight individual may also not show correct results due to increased mass. Other exclusions to the eGFR test are individuals who follow a strict vegan diet or ingest little to no protein.

You may also have to bear in mind that different conditions may affect the eGFR blood test calculations. In such cases, your doctor may recommend that you repeat your creatinine tests over a period and the calculate eGFR each time. If your report stays constant over this period, your doctor may recommend further medication or action to correct kidney malfunction.

Kidney disease can occur because of a wide range of problems that start from infections and inflammation all the way to autoimmune disease related problems like diabetes. Diabetes and high blood pressures are a vicious cycle of problems that will cause renal failure at some time. Note that when diabetes is not controlled, the kidneys are damaged, and eventually, the whole body will start to give way. It has been shown that continuous monitoring of eGFR levels has really made a great difference to the amount of problems that you have to deal with. Again note that this is not a test that is regularly ordered.