Fasting C-peptide level question

Got my latest lab results. First, I am super happy, because my HbA1c is 5.1% :grin: With few hypos!

My C-peptide level was 0.46 ng/ml. That was at fasting state (this is required prior to taking the sample). The blood sample was taken in the morning, so I had bolused for the morning BG rise previously. In August, the level had been at 0.81 ng/ml.

The thing is, my insulin needs have increased significantly since then. I was taking about 10-12 units of Tresiba back then. Now I need 20-21. My I:C ratio did not change all that much, it mostly just increased in variance over the day. And, morning BG rise was not present back then, but it is now. The amount of basal plus the morning rise indicate a fading honeymoon to me … but 0.46 ng/ml sounds like there’s still a significant amount of endogenous production going on. If so, where is it, why do I need that much more insulin? It is also noteworthy that I haven’t gotten more insulin resistant. 1 unit still brings my BG down by ~40-60 mg/dL. So, any ideas? Or is the C-peptide level completely meaningless here?

What was blood glucose level when taken?

Unless it was significantly elevated, that c peptide level is not meaningful… especially since you’re taking exogenous insulin

The BG level was at 82 mg/dL.

Then it’s meaningless, unless it was substantially elevated, or zero. Whatever the level was at that moment, it was adequate to keep your blood sugar right where it should be. It was not elevated which would indicate resistance, although it was below reference range, that means nothing because your blood sugar was normal and you’re taking exogenous insulin.

This is a topic that is widely misunderstood.

But I’m just a random internet guy, I’d recommend discussing with your doc…

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