My blood glucose levels are raised, so I was asked to take a fasting C Peptide test to check for the insulin production in my body and decide on further treatment. But, I see that labs also offer insulin tests, so why not directly go for an insulin test? What’s the difference between the two?
Yes, both the tests are different. The insulin test measures total insulin present in the bloodstream/urine, irrespective of its source. The insulin produced in the body is short-lived in the bloodstream; hence it cannot accurately diagnose if you are suffering from Type 1 or 2 Diabetes.
Whereas C- peptide is a pre-marker of insulin in the body. The C-peptide test tells the difference between the amount of insulin produced by the body and the amount injected. Hence, it’s a more reliable marker than insulin.
While low levels/no level of C peptide concludes that your diabetes is of Type 1, wherein your body is unable to produce insulin, high levels of C- peptide conclude that diabetes is Type 2 (insulin resistance), where there is insulin, but it cannot be used by the body appropriately.
Based on this test, the doctor can also decide whether medicines along with insulin can control your sugar or not.
Read more about C-Peptide test