What is C-peptide?

This test measures the amount of C-peptide in the blood. C-peptide and insulin are produced in the pancreas at the same rate and released into the bloodstream in equal amounts when insulin is required in response to increased glucose levels. C-peptide stays in the bloodstream longer than insulin, making it a useful marker of insulin production. It can be used to differentiate between Type I and Type II diabetes.

Low or no C-peptide means that your pancreas is producing little or no insulin. This could be normal if you have not eaten recently, as your blood sugar and insulin levels are naturally low when fasting.

Why test C-peptide?

Health Check
Discover your risk factors for lifestyle diseases in time to do something about them.

Health History
A family or personal history of blood sugar problems such as diabetes, smoking, drinking, being overweight, and/or poor diet.

To monitor or evaluate the impact of your supplements or see how much to take.

What causes low C-peptide levels?

Low C-peptide levels suggest that your pancreas isn’t working well, and your body isn’t making enough insulin. Possible reasons include diabetes Type I and Type II, insulin therapy, low blood glucose in diabetics on insulin, long periods of fasting or starvation, and poor pancreas function from, for example, pancreatitis. 

What causes high C-peptide levels?

A high level of C-peptide usually indicates a high level of insulin production, either in response to a high blood glucose caused by glucose intake and/or by insulin resistance. Higher than expected C-peptide levels can be caused by eating a high-carbohydrate meal, insulin resistance, obesity, kidney disease, cortisol excess due to Cushing syndrome and occasionally insulin-producing tumours, which are usually benign. Some medications increase C-peptide, including diabetes medications and glucocorticoids. Pregnancy can increase C-peptide levels.

More information

Repeat C-peptide tests should be undertaken by the same laboratory using the same method. For instance, if you have previously had a test done at Karolinska you should repeat the test at Karolinska.


The day before

Do not eat or drink anything except water for at least 10 (preferably 12) hours before taking this test.

On the day
Remember to take I.D. with you when going to take a test. Arrive early and sit down quietly for 15 minutes before taking a test.

© 2024 Nordic Wellth AB Terms Of Use