The GFR number that results from the GFR test shows the stage of kidney disease in the patient, with higher numbers indicating better kidney function and numbers lower than 90 showing some loss of kidney function, according to the National Kidney Foundation. Normal rates range from 90 to 120 depending on age, states MedlinePlus.
GFR stands for glomerular filtration rate, states MedlinePlus. This test uses the patient's blood creatine levels, age, gender and body size to determine how fast the blood is moving through the kidneys. Estimated GFR or eGFR are alternate names for the test.
The precise number that results from a GFR test gives a good picture of how far any kidney problems have progressed, according to the National Kidney Foundation. Patients with numbers of 90 or greater may have early kidney disease, but their kidneys are still functioning properly. Numbers from 60 to 89 indicate a mild loss of function, while numbers between 44 and 59 show a moderate function loss indicative of true kidney disease. Numbers from 30 to 44 show more deterioration, and numbers from 15 to 29 show severe loss of function. Numbers under 15 indicate kidney failure.
A GFR rate under 60 for three consecutive months constitutes a diagnosis of kidney disease, maintains the National Kidney Foundation. Early detection provides options for slowing the progress of the condition.