Hi pinkjude. We get lots of questions on the topic of what the numbers mean and especially how finger prick readings relate to HbA1c. They are related but you cannot get one from the other, all you can do is get a rough idea.
Let me do a Jonathan Van-Tam.....
Think of it like looking at Fair Isle sweater, you know one of those with a complicated multi coloured repeating pattern.
The HbA1c is equivalent to seeing the sweater hanging on a hanger. You get a good view of the overall impact, see the pattern well but you cannot see enough detail to work out how it was made.
The finger prick reading is like looking at the same pattern through a magnifying glass so that you can only see a couple of stitches. You can tell a lot about those stitches but you have no idea what the overall pattern looks like. Move your magnifying glass around so you see more and more stitches and you might be able to say something more about the pattern but it will always be a guess. To appreciate it there is nothing like dumping the magnifying glass, hanging the sweater on a hanger, so that you can see the thing as a whole.
When I looked at how to approach testing I came to these sorts of ideas to tell me whether I was on the right track or not. I took readings before and after meals, first thing in the morning and last thing at night. Not every meal every day, but what I tried to do was to cover all times of day by looking a breakfast for a couple of days, lunch for a couple, evening meal for some more. That way I could get a decent idea of my blood glucose range and a measure of the long term average.
To continue the Fair Isle sweater thing.... After a couple of weeks or so I had no real idea of the overall pattern but I knew some thing about what colour wools were being used and could begin to make guesses about the pattern repeat. It was enough for me to make some sensible dietary changes to eliminate those things that made big jarring statements in the pattern. I knew I was aiming for something neutral and subdued, not Joseph's amazing technicolour dream coat knitted by a crofter.
Finished up by revising my diet such that no matter what, I rarely got a reading in double figures and kept the overall long term average around 6. This gave me a HbA1c of 38, down from the high of 82 where I was getting spot readings in the high teens, low 20's. I don't have an average for that period but I am guessing it was in double figures.
So, my thought for you is not to think about your HbA1c when looking at your finger prick readings. Look at those as a means of adjusting your diet to eliminate those things which give readings into double figures a couple of hours after eating. If by doing that you can keep your spot readings in the range 5 -10, and if needed, lose a bit of weight then the HbA1c will take care of itself.
Usual disclaimers.... only applies to T2's using diet, exercise and perhaps a bit of medication to control things and because it worked for me, it does not mean it will work for you!