A normal eGFR ranges from 90 to 120 milliliters per minute per 1.73 square meters, states MedlinePlus. An eGFR is calculated using a formula that accounts for age, ethnicity, creatinine level, gender, height and weight.
The eGFR test indicates how well the kidneys are filtering waste from the blood, according to MedlinePlus. Doctors typically order the test when a patient experiences signs or symptoms of kidney failure. An eGFR may also be used to determine the severity of kidney disease. An eGFR of less than 60 for three months or more indicates chronic kidney disease. An eGFR less than 15 usually signals kidney failure and requires prompt medical care.