The acronym eGFR stands for estimated glomerular filtration rate, according to the American Kidney Fund. An eGFR test is used to test how well the kidneys are working by calculating creatinine levels found in the blood, taking into account the age, sex and race of the patient.
Creatinine is normally filtered out of the body when kidneys are healthy, notes the American Kidney Fund. A normal eGFR is 60 or more. Although this test is a helpful tool used to determine kidney function, many things can affect the accuracy of the test. Individuals who are obese, under the age of 18, or extremely athletic and muscular may have inaccurate results.