Why get tested?
To monitor insulin production by the beta cells in the pancreas and to help determine the cause of hypoglycemia

When to get tested?
If you have type 1 or type 2 diabetes or metabolic syndrome and your doctor wants to determine if you are producing enough of your own insulin, if you are insulin resistant, or if it is time to supplement oral medication with insulin injections; it is also ordered to support a decision to place a patient on an insulin pump; your doctor may also order a C-peptide test if you have documented hypoglycemia

Sample required?
A blood sample drawn from a vein in your arm and sometimes a 24-hour urine sample

Note: Ask your doctor if you need to fast before having this test performed.