[adrianconnelly]

Does anyone know what formula is used by the A1c estimator? It seems there are several formulas (formulae?) that are used by various professionals/organisations etc, including...

1. A1c = (avg BGL + 100) ÷ 36
2. A1c = (avg BGL + 77.3) ÷ 35.6
3. A1c = (avg BGL + 86) ÷ 33.3
(BGLs are in mg/dL)

I am confused, and would like to know what the one used in the GlucoseBuddy estimator is. Is it one of these, or is there another one?

Many thanks.
Adrian

[dano]

Adrian;

If you are not getting the same answer it is probably not one of those. Try this one: A1C Calc Thread:
http://www.glucosebuddy.com/forum/showthread.php?t=151

[adrianconnelly]

Hi Dano

Many thanks. I feel like a proper dill 'cause I really should have looked first before asking the basic question.

But it raises another one, if you can bear it.

Is the figure used for BG in your formula simply the average for all one's readings over the last 90 days or is it the average of Out Of Bed (fasting) readings, or is it something else again?

If I use the raw average of all my BG readings I don't get the same a1c answer as the estimator. If I use the eAG figure, though, it works fine. But I don't know if that's just co-incidence or what the eAG actually represents (other than it stands for Estimated Average Glucose). How is eAG calculated?

[I'm trying to explain all this to someone who is T2 but who isn't good at managing their condition, nor diligent at even taking BG readings. Their last a1c was a dreadful 16 and there's a lot of 'don't wanna know about it' going on. I'd like to help if I can.]

Thanks
Adrian

[dano]

Adrian;

I will try to answer your questions the best that I can:

The figure used for BG, in the formula that I used, is simply the average for one's blood glucose readings over the last 90 days. The Glucose Buddy (GB) WebSite (A1c Calculator) is set up this way, as well, to mimic the A1c obtained from the Lab, since most of us have the blood work done every three (3) months. It should be noted that, based on what I previously found, the formula that I used, the GB App and the majority of the US blood glucose meters are apparently set up to use the Average "Plasma Blood" Glucose (mg/dl). Please be advised that the Labs in the US use Average "Whole Blood" Glucose (mg/dl) [eAG] to determine the A1c or atleast I believe this to be true. I don't know for sure how this is calculated by the website, but according to my notes, gathered nearly a year ago, the equations are shown at the following website. Reference: http://www.obfocus.com/calculators/HemoglobinA1C.htm.

When I originally posted this information the GB WebSite did not calculate one's A1c until after 90 days of information had been input into the data base. The information posted in the thread works fine up to 90 days and it seems to work well if you use the average blood sugar value for the 90 day period generated by the Glucose Buddy (GB) WebSite (A1c Calculator). Please be advised that the average blood sugar, shown in the GB App; My Info; Average, is an average of all the data that has been input into the App data base to date.

Good luck in trying to explain this to the other person, I wish them well!