Ask the Diabetes Educator Archive


My new insurance company is requiring a C-Peptide test before they will pre certify my insulin pump supplies. I have never heard of this test before and was wanting to know what it is testing (my doctor refuses to tell me, and yes, I am switching PCP's immediately because of this). She also ordered a Pro Insulin test. I don't know what this one is for either. I have been diabetic for 33 years and have never had either of these tests done. Could you please inform me as to what these tests measure?

A C-peptide test is basically the same as the Pro-insulin. C-peptide is an amino acid sequence in the beta cells of the pancreas that is necessary for insulin production. The test will determine where you fall in the range of producing C-peptide. People with Type 1 diabetes generally will show no or trace production. This test is not routinely done for Type 2's; endocrinologists will generally order it only for Type 1's. You may want to convey your concerns to the nursing staff if you cannot talk to your physician directly.

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