Robbity
Expert
- Messages
- 6,700
- Type of diabetes
- Type 2
- Treatment type
- Diet only
How do you calculate HbA1c from meter averages? Do you average the am FBG's?
No - IMO they are the least useful for me of all my readings - my pre and post meal checks are the ones I take most heed of.
As a rough guide: 3 months meter overall averages (so fasting, pre, post meal, and any other in between readings I take for whatever reason), and my meter does all this working out for me, then as I said I use this average in the converter on our main site: https://www.diabetes.co.uk/hba1c-units-converter.html.
And it is only a rough guide because it (consistently) gives me a level a couple of points lower than my actual HbA1c, but my Libre would have me a paragon of virtue well and truly non-diabetic when I last did a check on that, so even lower again! So at best these tools can be reasonable pointers, but definitely are not to be taken as absolute gospel.

Robbity