# Re: [IPk] BGs and HbA1c

```I've actually managed to predict accurately my last 2 HbA1c's, using the
following formula. (I use a Medisense Optium - also called a Precision Xtra
- meter, but these seem to work for most meter readings. It will depend
somewhat on how often you test, but it gives reasonably accurate ball park
numbers for most - meaning people who test 3-6x/day or more). The "average
BG reading" is the average over the last month.

Using plasma glucose readings (which most meters these days measure, but
your meter manual/guidelines should tell you whether it measures plasma or
whole blood):

HbA1c = (average blood glucose {in mmol/l} + 4.2944)w 1.9777
HbA1c = (average blood glucose {in mg/dL} + 77.3)w 35.6

If you use an older meter which measures whole blood - and some newer ones,
including the Optium, for example - the mean (average) glucose reading
measures lower and so the HbA1c is actually higher than results using the
above formula. The below should be used:

HbA1c = (average blood glucose {in mmol/l} + 4.778)w 1.85
HbA1c = (average blood glucose {in mg/dL} + 86)w 33.3

I'd be interested to know if others find these accurate or if it's just me!

Tori

At 07:01 PM 20/07/2003, you wrote:
>Yes, of course, I'd already writen too much, and the difference between
>the hba1c and meter average (even if the meter is used every hour, and
>at no other time) is something which has a far bigger impact, of course
>(and one can set one's meter average on the computer to whatever one
>likes, at least with my meter: on meter it's 2 weeks, though.  It would
>be nice to have a 'mimic the hba1c and predict it' function, too ...

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