HbA1c Higher than it should be

HI,
I've just got my HbA1c back and its gone from 7% to 7.7%. During the past few months I've been low carbing and my levels have hardly every gone over 10 and have significantly improved since my last HbA1c. My meter tells me that my average over the past 3 months is 7.6 mmol/l, which should give me an HbA1c of 6%. An HbA1c of 7.7% means I've been averaging at 11 mmol/l, which just isn't true. I regularly check my levels during the night and they stay constant.

For a few years now I've suspected that my HbA1c is higher than what you would expect from my average levels. Does anyone else have an HbA1c higher than they expect? Has anyone gone low-carb and had their HbA1c go up?

I'm totally devastated, I've put so much effort into it, I know my levels are good (I record before and after every meal), I know I've had way fewer highs than my last HbA1c and I definitely have not got an average of 11 mmol/l. The only thing that I can think of is that my red blood cells are living longer.

I'm not going to give up don't worry, although I was certain I'd be in the 6 club this time round. I think the culprit may be the holiday that I had 5 weeks before the test, where I was in Hong Kong for a week and I was in the teens most of the time (impossible to low-carb). I also had to attend a company conference two weeks ago for two days and I was in the teens a bit there too (again, not possible to low-carb).

Apart from that my day-to-day levels have been great, better than at any time really - I've not had a reading over 10 for one week now. My day job is to model the concentrations of drugs (for oncology) in the blood stream and I've applied my knowledge to my glucose levels for the past couple of years. I've been saying to doctors for a couple of years now that my HbA1c and average sugar levels are inconsistent, but no-one is listening. I'm at a new surgery now and I'm going to ask to have test for iron, vitamin B12 and folate deficiency as these can make red blood cells live longer and hence push up an HbA1c. It may not be the cause, but at least I can then rule it out. I'm also going to ask for monthly HbA1c tests until I figure out what's going on.

I've checked my meter with control solution and it gave perfect result, but I will switch to a MyLife Pura which is supposedly the most accurate and precise.