C-Peptide

Pancreases produce hormone called insulin.  Insulin is a hormone that controls the body's glucose (blood sugar) levels. Glucose is your body's main source of energy. If your body doesn't make the right amount of insulin, it may be a sign of diabetes. Pancreases also produce a substance known as C peptide along with insulin. Insulin and C peptide are produced at the same time and roughly in equal amount as well. Hence, it is good indicator to monitor how much insulin is being produced in the body.

Your doctor will ask you to do this test if you are showing any signs and symptoms of diabetes, however unsure whether type I or II diabetes. It can also be done if you are showing symptoms of hypoglycaemia (low sugar levels) like:

• Sweating
• Irregular heartbeat
• Confusion
• Fatigue
• Vision disturbance

A C-peptide test is often used to help tell the difference between type 1 and type 2 diabetes. In type 1 diabetes, pancreas makes little to no insulin,  hencelittle or no C-peptide. While in type 2 diabetes, the body makes required or normal amount of insulin, but doesn't use it well. This can cause C-peptide levels to be higher than normal. This test is used for

• To find cause of hypoglycemia
• To monitor diabetes treatment
• To monitor pancreatic condition such as inflammation or tumor.

A C-peptide test can provide important information about the type of diabetes you have and whether or not your diabetes treatment is working well. But it is not used to diagnose diabetes. Other tests, such as blood glucose and urine glucose, are used to screen and diagnose diabetes

Other names: insulin C-peptide, connecting peptide insulin, proinsulin C-peptide

Normal range

0.5 to 2.0 ng/mL

Requirements

You may need to fast (not eat or drink) for 8–12 hours before a C-peptide blood test.