The C-peptide test is measured to detect pancreatic dysfunction and is used to diagnose type I and type II diabetes. The pancreas produces c-peptide and insulin in equal amounts during blood glucose regulation. Insulin degrades faster while c-peptide stays longer, which serves as an important tool to monitor and treat conditions such as hypoglycemia, insulinoma, and factitious hypoglycemia. Recommended Patient should fast for 8 hours.