I was diagnosed with type 1 diabetes a few years ago. There are some lifestyle choices I can’t get away from that require that I eat large meals. How does a C-peptide level of 0.8 convert into units (U-100) of insulin by weight and time?

A fasting C-peptide level of 0.8 would be at the lower level of normal, assuming that it was expressed in ng/ml (which is the usual format). This would be consistent with a diagnosis of type 1 diabetes or perhaps, in your case, with Latent Autoimmune Diabetes in Adults (LADA).

C-peptide is used as a reliable measure of residual insulin production when a person is receiving additional insulin by injection. In practise though, although it is possible to calculate how many units of insulin were made at the same time as the C-peptide, this is not clinically of value as the two substances are treated differently in the body. Indeed, that is one reason why insulin amounts are usually expressed in Units.

I was not quite sure of the connection between this question and the need to eat large meals, but the C-peptide level would not be of great relevance in calculating the right dose of insulin to maintain good control.

DOB