Why get tested?
To diagnose kidney malfunction if the eGFR (estimate of glomerular filtration rate) is unsuitable

When to get tested?
If your doctor thinks that you may have a problem affecting the function of your kidneys, such as an obstruction within the kidney, acute or chronic kidney failure, dehydration, shock, or another disease, such as congestive heart failure. The most common test for kidney function is serum creatinine and the eGFR, however in some patients further testing is required.

Sample required?
Both a urine sample (24-hour collection) and a blood sample drawn from a vein in your arm