Insulin Pump and C-Peptide and GAD 65Tests

I have been what I thought was a Type 2 diabetic for 8 years, but was always treated by my internist. I now have an endo and the question has come up whether I’m a type 2 or type 1.5 because I progressed to insulin within 2 years of diagnosis. I started using an insulin pump 3 months ago and love it. Now I’m suppose to have a c-peptide and GAD-65 test due. Does anyone know if it’s okay that I’ve been pumping insulin in? I don’t want the test to show the insulin from the pump like its my body making the insulin. The endo didn’t tell me to stop the pump before the test, I’m just curious and I certainly don’t want to “waste the test” or get incorrect results because of my pump. This may not be the right place to ask the question, but of course my doc’s office is closed today and I’m suppose to go to the lab this morning. Thanks for your help

The c-peptide your body produces relies on insulin produced by your body. It's the chemical that breaks down insulin produced by the pancreas only.

The analogues of insulin we inject or pump are already in a form that does not need c-peptide. So you will be perfectly ok to have the c-peptide test no matter how much insulin you are injecting or pumping.

The c-peptide test determines how much insulin your body is producing only, not how much is injected.

Hope that helps!

It absolutely does help. Thanks. The question popped into my head in the shower this morning and I had a little moment of panic, like I forgot to ask the endo the right question or something, lol. Have a great Christmas