High A1C doesn't match my meter readings

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Permalink Reply by John on January 9, 2008 at 6:44pm

"Two individuals with the same average blood sugar can have A1C values that differ by as much as 1 percentage point)"

From: http://en.wikipedia.org/wiki/Glycosylated_hemoglobin

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Permalink Reply by Kevin McMahon on January 9, 2008 at 7:14pm

Typical A1c test methods are off by +/- 0.3 frequently and by +/- 0.5 or more at least 3% of the time according to research published by Larry Fox and also the team at DirecNet so it's hard to say. There is also the possibility that your blood chemistry contains one or more aspects that interfere with the A1c test; things called hemoglobinopathies which are not typically screened for. The NIH just published an advisory on this, too.

Read more here...

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Permalink Reply by Hana Rous on January 10, 2008 at 3:53am

I've never experienced anything like this, but have you tried all the checks on your own meter? Also do you keep a running average on your meter? Look in Dr Bernstein's book or on the web to see if your average is a long way off the expected A1c. I'm in England and so only really know the numbers in mmol/l where the lower numbers basically almost line up, so an average of 5mmol/l corresponds to an A1c of 5%. also is your meter calibrated correctly? Sounds like a silly question, but I scared myself the other evening with a reading of 8.5mmol/l (,about150mg/dl) when I knew it shouldn't be that high. I had stupidly forgotten to recalibrate after I opened a new pack of strips. Even after having this meter a couple of years, I forgot.
Having said all that, 6.1% and 5.6% are way better than many people manage to achieve. I'm just waiting on my latest results and will be happy with 5.5%.
Lastly, in my jumbled thinking,you say your numbers have been a little higher lately. How long since your previous test? A red cell has a life of about 120 days and so A1c is more accurate over that length of time.

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Permalink Reply by Libby on January 10, 2008 at 6:38am

I do callibrate my strips and have tested my meter. Plus my meter always corresponds to how I feel and to the number of carbs I eat. For example, when I accidently drank a real soda, I was at 220, when I eat a small apple, I go up to 130. I'm guessing I am just an oddball whose A1C does not correspond because my first A1C of 7.2 was way, way higher than my BG suggested. I have a very robust second phase insulin release and never go much over 180 at 1/2 an hour, even with a high carb load. Then my BG drops rapidly till I get a fairly low rebound and some hypo symptoms. So on diagnosis, I was bouncing between 180 and 60 with a fasting rate of 80. Shouldn't have translated to a 7.2, which is an AVERAGE of about 170.

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Permalink Reply by Hana Rous on January 10, 2008 at 8:01am

I have no more ideas, but I noticed one thing I find interesting in your reply. you say your meter corresponds to how you feel. That's fascinating. I don't feel any different unless I go very low, which rarely happens as my medication shouldn't allow it. I'm using Metformin and Starlix. I never go very high, so I don't know how that would feel or even if I'd know.

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Permalink Reply by Libby on January 10, 2008 at 8:25am

I just spoke with the school nurse and she suggested it might be tie for a small amount of basal insulin. And that I should have my fructose level checked. I'll try those things. As to how I feel, I'm pretty sensitive to anything over 150 or under 70 and those are rare numbers these days for me. I can't imagine that my true BG numbers are 40 points higher than I am getting since I would notice if I was going high enough to average 125.

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Permalink Reply by David Yolleck on January 14, 2009 at 9:21am

There are any number of reasons by which A1c would not seem to correspond with glucose meter measurements.

One unlikely possibility, that I just made up, is that different people might have different rates at which glucose binds with proteins. A person with a high binding rate would tend to have higher glycated hemoglobin values, for a given average glucose value, as against someone with a low binding rate. Perhaps there might be some (unknown) enzyme that is, at least in part, responsible such variation. Perhaps, too, the rate of binding might, in part, account for varying degrees of suscepibility to secondary complications.

There is no cause to believe a word of what I've just written. I know of nothing that supports it.

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Permalink Reply by MeadowLark on January 10, 2008 at 10:17am

umm an off idea? Might you need to put a new set of batteries in your meter? Sometimes my numbers look weird and I change for a new set and things match up better with the Dr office.
Huggles
MeadowLark

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Permalink Reply by gretchen on January 10, 2008 at 5:16pm

I've always had A1cs higher than my BGs would seem to indicate. I even tried a CGM to see if I was going high at night or at unexpected times of the day, when I wouldn't think to test. I wasn't.

I've tried talking with the techs at LifeScan to see if possibly something in my body chemistry or vitamins could be causing falsely low BGs on my meter, but they couldn't come up with anything (not that they tried very hard; just spouted the usual stuff).

Remember that the A1c assumes your red blood cells live 120 days. If for some reason they live longer than that (RBCs of people without spleens do live longer), your A1c will be higher than expected. If they live a shorter time than that, for instance if you've given blood or if you're anemic, your A1c will be lower than expected.

Researchers used to think that some people are just "good glycators" and glycate hemoglobin more robustly than others. That's possible. But I've seen recent papers suggesting it's more likely red blood cells that live longer than usual.

I think the important thing to focus on is whether your A1c, done at the same lab, is going up or down consistently, or staying the same.

Many medical people assume that you're testing wrong or sneaking sugary treats and not mentioning them. Ignore them. There's probably something in your physiology that is causing different A1cs than expected.

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Permalink Reply by Hana Rous on January 11, 2008 at 2:01am

I'm picking up on your comment about people's assumptions.
I'm maddened by the assumption that if something is anomalous, you are telling lies. I don't get this with my present health-care team, they're great! ( even if they don't approve of low-carb diets) However I do remember getting it when my daughter, now a married woman, was small. The receptionist, who answers the health centre phone got the sharp end of my tongue at least once.

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Permalink Reply by gretchen on January 11, 2008 at 6:58am

It's not just health care people. You can spend 5 hours trying to solve a complex problem with your computer system, finally give up and call tech support, sit on the phone for 30 minutes, and then have the person ask, "Is it plugged in?"

The problem is that many people do forget to plug the computer in and do use the wrong strips or don't wash their hands before testing and do say they've been following their diets when they're not.

Those of us who don't fit the standard profile just have to learn to let these things wash over us.

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Permalink Reply by Denise on January 14, 2009 at 10:14am

I am so glad you said this--- RBCs of people without spleens do live longer, your A1c will be higher than expected..they never told me this when they had to take my spleen out--you'd think they'd a told a diabetic this--well--guess not given everything else they don't tell us--but they should! My BG took a .6 jump after my surgery, i am having a deveil of a time getting it back down to 6--and it is higher than my meter (and CGMS) average

Do you happen to know offhand if it throws anything else off (yes I know I can google--but no sense doing a lot of search if someone lese has already done it)

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