| Helen,
Typically people with autoimmune Type 1.5 deteriorate over 4 years, you've been going in the opposite direction, so it is quite possible that you might have some other condition which impaired your beta cell function and which is slowly resolving.
There are so many different underlying causes of beta cell failure, and doctors don't do much testing to isolate what is going on. The C-peptide test only tells you that insulin isn't being produced, not why.
You might want to ask if it would be possible to get a new C-peptide test to see if you are getting more insulin production. But it is also possible that your insulin resistance might have decreased, making your body more efficient with what it gets. This can happen when you lower blood sugars as high blood sugars cause insulin resistance. My insulin sensitivity increased dramatically when I lowered my typical post-prandial reading from 180 to 140 and again when I brought it from 140 down to about 110.
Whatever is going on, it's very good news for you!
__________________
A1c 5.7% 10 years after diagnosis.
| 
