A kidney function test is recommended for people with diabetes and high blood pressure, as well those with a family history of diabetes, high blood pressure or kidney disease, explains the National Kidney Foundation. The test measures creatinine levels in the blood after which the glomerular filtration rate is calculated.
GFR is the best way to tell how well the kidney functions and should be done every year in patients who are at risk, according to the National Kidney Foundation. Patients should also have a urinalysis to check for elevated levels of albumin in the urine because it may indicate early stages of disease.
Chronic kidney disease is diagnosed in patients with a GFR of less than 60 for more than three months or those with a normal GFR but elevated levels of albumin in the urine, explains the National Kidney Foundation. Stage 1 CKD means that normal kidney function is preserved but damage is present. This is diagnosed when the GFR is greater than 90. Stage 2 CKD is diagnosed when the GFR is between 89 and 60, and means that kidney damage is present with a mild loss of function.
Stage 3a CKD is when the GRF falls to levels below 59 and above 44 with mild to moderate loss of function, describes the National Kidney Foundation. Stage 3b CKD indicates moderate to severe loss of function with a GFR between 44 and 30. Patients with a GFR between 29 and 15 have Stage 4 CKD and a severe loss of function. When GFR falls below 15, the diagnosis is kidney failure.