Why get tested?
To determine the function of your kidneys. The GFR (glomerular filtration rate) is the best marker of kidney function.

When to get tested?
To look for evidence of kidney damage or to monitor changes in kidney function if you already have kidney disease.

Sample required?
eGFR is calculated using your age, gender, and serum creatinine (requires a blood sample from a vein in your arm). The calculated result is usually included on the pathology report with every request for a creatinine in adults.