Yes, they actually know quite a bit about what effects A1C which shows many of the limitations of it.

I have read the same that the last 30 days before the test has greater effect on the number.

They also know that fasting blood sugars have almost no bearing on A1C

Other factors that can mess with the "true reading"

Using aspirin near every day to manage pain or taking vitamin C or E supplements can give you an artificially lower reading (now you could use this to maybe trick your doctor or make yourself feel better, but it won't trick the Beast).

Drinking alcohol on a daily basis can cause an artificially high number.

Also, while the (story) is that it measures the past 90 days of what is going on, some blood cells can actually live as much as 120 days which would be four months and would end up with far more sugar stuck to them then a "3 month old" yet that higher count would only be factored for 3 months - so again, artificially high (but that probably always comes out in the wash).

But most importantly, A1C doesn't give any indication of how high or how low you are actually going - simply gives an average which could be a dangerous way to treat.

In general they say an A1C of say 6.0 "should prevent most complications".

At 6.0 your "average blood sugar" would be 126 or 7.0 mmols - a nice safe average.

But it's an Average - and essentially over 144 or 8.0 mmols you are doing some (cumulative) vascular damage.

Now if your "range" was say 108 - 144 or 6.0 - 8.0 you would be fine - average would be 126/7.0 A1C 6.0

But if instead your average was 90 - 162 or 5.0 - 9.0 average would "still be" 126/7.0 with the same 6.0 A1C but all those levels above 144/8.0 would be "hurting you a little".

So the first example would likely leave you complication free while the second would likely cause some level of neuropathy, would damage your heart, brain, eyes and kidneys.

And for that reason alone is why I test at home. A1C doesn't tell you "really" how well you are controlled but rather what your "average level of control" is.

For best control yes, A1C is important but so is staying "in safe range" at least 90% of the time.

@A DiabetesTeam Member - simple answer is NO, it doesn't work like that.

It can take months to years (unless some infection or drug reaction etc does physiological damage) to effect either your insulin production or your insulin resistance.

So having a day or two of high blood sugar is NOT like falling badly on your ankle and busting it.

Rather it is the repeated and sustained high sugars (higher than 8.7 mmols) that will eventually either destroy the very small blood vessels in the pancreas (and your brain, eyes and kidneys as well) OR;

If "your diabetes" is more "insulin resistance" than an insulin production problem (which is typically the situation in the first few years following diagnosis for over 80% of us), then continued high sugars, in addition to causing the (microvascular) small blood vessel damage will cause the pancreas to kinda go into overload trying to pump out enough insulin to deal with all the sugar.

That (system) isn't exactly "fragile" and it can a number of years before you burn it out - but it really is dependent on duration of disease.

The longer you have had diabetes the more "punches and kicks" the system is taken and just like a boxer who could take some heavy punches in the first couple rounds and shake them, a love tap might send them to the mat by the 8th or 9th round.

And that is why the better control you get "sooner" and keep as long as possible is better - you don't wear down your system as badly so it will hang on longer.

At least from most of the studies I have read that looked as such things, it appears that you have about 3 years where you can "learn the ropes" and not do significant long term damage - but of course, the more stringent you are keeping control the better.

So shake it off - work towards better control and don't worry about the "blips".

WE ALL Blip - for two weeks I was running almost a point (1 mmol) higher than normal - it averages out as long as it goes back to your (my) normal. What you watch for is a trend - so it goes up that 1.5 but doesn't come back down within a month (give it a month).

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A Diabete...

Yes, stress can jack it up, a low grade infection, changes to your schedule/work schedule, seasonal changes - when the clocks change that can throw things out of whack for a week or more.

However, as well as I understand on an (intellectual level) that it's "normal" to sometimes run higher or lower for a week or two with no real explanation, it still does cause me "some concern" if a (blip) lasts longer then a day or two and I can't explain (to my satisfaction) exactly why.

Human nature I guess.

But it really is watching for "trends" rather then some "bumps in the road" - sure, compare week over week and then month over month.

Try to remember that even an A1C test, which is the "diagnostic standard" is looking at a 90 day average - so a couple weeks of "higher" is cancelled back out by "many weeks" of "your normal" without changing that average very much at all.

I have read and also have been told by several internal specialists that the last 3-4 weeks leading up to our a1c test have a major impact on the results.
I'm going for mine in just over a week so we'll see.

Oh thank you, that makes sense, and your edit above is reassuring! I didn't realize they knew it was at 8.7 and above that damage happens. Good to know!
Thanks again! I'll keep watch