A C-peptide test is a blood test which is carried out to find out how much insulin your body is producing. This may be useful for determining whether you have type 1 or type 2 diabetes or whether you have insulin resistance.
A c-peptide test can be performed for any of the following reasons:
1. To distinguish whether you may have type 1 or type 2 diabetes.
2. To investigate whether you have insulin resistance.
3. To ascertain causes of hypoglycemia (low blood glucose levels).
4. To monitor insulin production after the removal of a tumour of the pancreas (insulinoma).
The reference range of C-peptide fasting for adults is 0.4 to 2.2 ng/ml and for children (<15 years old) is 0.4 to 2.1 ng/ml.
