Hi, yes you're right.What is a false high HbA1c ? that's a new one for me.
Interested rather than challenging what you say, I'd just thought it was what it is. There is a train of thought that if your blood cells are living longer (for example on a Ketogenic, therefore lower inflammatory, regime) then a given test would effectively take cells from a longer period, therefore would have more A1c products than would be expected in an average 3 month blood cell life period, so inflating the result - is that what you mean?
I would have thought in that scenario, a patient would be expected to have higher vit B12 though ... another thing to dig into...
[edit - didn't take long, and I totally retract - clearly a B12 deficiency itself causes longer red blood cell life, so gives that same effect, now to dig into why...]
There are lots of peer-reviewed articles you can find via Google Scholar.
I got told I had pre-diabetes and low B12 at the same time. About a month later, I got told I'm also anaemic. I feel there's something happening to my body that's linked. I'm also only just in the prediabetic range, so I'm curious if my HBA1c will go back to normal if my B12 deficiency and anaemia is addressed.
Your hunch about higher B12 is true, I believe, for those with Type 1. I think they can have higher B12 serum levels. And for type 2s on Metformin, that can cause a deficiency!