The eGFR test looks for signs of kidney damage. This is an especially useful test for patients with diabetes and/or high blood pressure, both of which can cause kidney problems. Reading the test scores correctly is very important, though. It’s perfectly normal, for example, for a 16-year-old to have an eGFR of 300 ml/min, while a 60-year-old may score 100 ml/min – yet in both cases the kidneys are fine. A score lower than 60 ml/min, however, indicates that kidney function is impaired.