High A1C even if blood sugars are in the 100's?

My fasting blood sugars have been 100 or less and when I test throughout the day my blood sugars are in a good range with occasional highs and lows of course. Is it possible that even if blood sugars are doing well, I can still have a high A1C reading?? What would cause this?

A bit more information in order to answer: How high was the A1C? Also you say "when you test throughout the day" but don't say when and how often you test. If for example, you weren't catching 2 hour pp spikes, that would certainly explain things! And when you say occasional highs and lows - how occasional and how high? Also remember the A1C is for a period of 3 months, though it is weighted more to the recent numbers. So if, for example you had a period of more highs 2 months ago that would be included.

You don't give a lot of details numberwise about your bg or A1C so it's hard to be specific in responding.

Just taking an extreme case of "100's": if you were at 190 most of the time, you would have an A1C in the 8.5-9.5% range.

There are also some red blood cell abnormalities that can cause A1C to not accurately represent average bg. e.g. sickle-cell disease will lower A1C below what you'd expect, and vitamin B12 and folate deficincies can raise A1C above what you'd expect.

The A1C is affected by the length of time that any highs persist. With finger pokes, it's really hard to get a completely accurate idea of when and for how long your BGs are going up. Are you able to gain access to a CGM, even if only for a trial period, to see where your spikes are occurring? It could be that you're rising significantly during times when you're not testing (such as when you're sleeping).

As others said, you have to tell more.
But if you measure often (6 or more) and your average is really off your A1C, I would change glucometer ...

Some people has A1C lower/higher than "usual" due to specific metabolism, but I would leave this as last resort to explain what you say (tell more!).

There are other factors that can greatly effect the A1c.

Even though the test protocols say you do not need to be fasting, you should be.
And never take the test if you sugars are high.
I try to be right at 100 for consistancy,

Also the test is checking how much of your RBCs are glycated. This happens when the red cell is created. The more sugar that is present the more likely that it will be glycated or glycosolated. Most RBS'c are produced at night and when you sleep, so High sugars at night can easily throw the test off considerably. This is why the A1c can give a average glucose over 3 months, because an RBC lives about 3 months.

If you can get a CGM it will do you a lot of good to see if you are going high post meals and at night, If not you can try just testing 2 hours after meals because that will be where the spikes will be normally.

Marilyn, What is a "good range", what is the occasional "high", and what does it mean "blood sugars are doing well"? And what is a "high A1c"? I'm always a questionner, and those are what I need defined for me.
For ME, I read into "good range"=100-110; "occasional highs" means once a week up to 150. 'Blood sugars are doing well" means 100-110; And a "high A1c" means above 6.5. Now I hope you're laughing with me, cause each of us has our own definitions of everything! Tell me what your definitions are! And thanks. It's an important question.

You are a damn demanding perfectionist LOL

So what is your A1C reading?
What you think may be high could be perfectly fine.