Why get tested?
To monitor insulin production by the beta cells in the pancreas and to help determine the cause of hypoglycaemia (low blood sugar)

When to get tested?
If you have type 1 or type 2 diabetes and your doctor wants to see if you are producing enough of your own insulin, if you are insulin resistant (when your body does not respond properly to insulin), or if it is time to supplement oral drugs with insulin injections. Your doctor also may request a C-peptide test if you have an episode of hypoglycaemia

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