Sunday, February 12, 2012

A1c Accuracy

The hemoglobin A1c test, usually referred to simply as the "A1c," can be accurately translated into our average blood glucose (BG) levels for the past three months or so, right? Wrong. On average, you can produce formulas that estimate the average BG levels for the average patient, but these formul...
3/23/09 5:05pm

while this is a good critique of the A1C, i feel it is somewhat of a smokescreen, in that trending A1C is always more important than a single (perhaps theoretically irreducible) measurement- in fact, one could critique any lab value along these lines, but it doesn't make the values invalid or inaccurate even if they deviate from the population norm- so trending A1C movement for an individual can be accurate even if it is varying from what is 'normal'- as Aristotle said, there is no science of the particular- but change in a particular can become a science- so i would integrate HgBA1C trend along with changes in weight, diet , and exercise as key pieces to modifying a diabetes plan of action, even if those pieces may be exotic

3/23/09 8:45pm

Frank, I'm afraid I don't follow your logic. I agree that A1c trends in an individual are more important than absolute numbers -- within reason. Keeping your A1c at 13 is not a great idea even if it's not increasing, and I always advise people not to compare their A1c with someone else's but to look for trends instead.

 

Nevertheless, many people want to know why their A1c doesn't jibe with their meter readings. And many physicians seem to accept the A1c-to-average-BG formulas. Hence I wanted people to understand that these formulas don't apply to everyone so they'd be able to discuss this with their doctor.

Anonymous
Nicky
3/25/09 12:55pm

My Granddaughter was treated for Gestational Diabetes, and 2 months after safely delivering a 1 month premie, (due to an amniotic fluid leakage that put the baby in jeopardy) we found out that she had been bleeding internally as a result of undiagnosed Chrones Disease! 

During her pregnancy, even while taking the best vitamin protocol, she was anemic, iron deficient and feeling less than her normal healthy & bubbly self.

After 2 months of steroid treatment and terrible weight loss she has had surgery, .  The outcome was better than any of us had even dared to hope and her surgeon suggested that she could safely complete another pregnancy after recovering.

She is doing well now, her baby is a healthy 9 month old, and she is preparing to get pregnant again soon, as her Gastrointerologist says the sooner the better, if she wants another child.

Is it possible that she really didn't have Gestational Diabetes? Would it be helpful to add this information to the mix, or would it be better to just let her be treated for Gestational Diabetes in the event that comes up again? 

3/25/09 1:40pm

"Is it possible that she really didn't have Gestational Diabetes? Would it be helpful to add this information to the mix, or would it be better to just let her be treated for Gestational Diabetes in the event that comes up again?"

 

According to that article, yes, it's possible she didn't have GDM. If it were me, I'd print out a copy of that article on GDM and show it to her doctor and ask his opinion.

 

Assuming she learned how to measure BG in the last pregnancy, I think the best approach would be to carefully monitor her BGs in this one, just in case. I wouldn't "treat" it unless they were high, unless by "treat" you meant a careful diet. That's never a bad thing.

Anonymous
sammy
7/ 7/09 5:46pm

My child has had higher sugars in three months...but she diets and fasts before going in to the doctor thus faking overall resuts!??

7/ 8/09 6:17pm

If your child is a teenager, I think such behavior is not uncommon. Some teens write fake numbers in their log books. The A1c was supposed to control for that, but having a lot of lows can cancel out a lot of highs, and because the A1c is heavily weighted toward recent weeks, very strict control for a couple of weeks would give inaccurate assessment of her control over the past few months.

 

Teenagers think the future will never come. I sure did. As she gains maturity, such behavior should change and she'll realize that "cheating" with her BG results is only harming her.

9/13/09 6:00pm

Hi Gretchen,

 

I have thalassemia and last month was dx'ed as T2 diabetes. I'm having an A1C test next week, though I've read that because of the thalassemia, the results may not be accurately translated into my average blood glucose levels for the past three months.Is there another test that can be done that can?

 

Thanks,

Nicole

9/13/09 8:42pm

Yes. Ask for the fructosamine test. This isn't used much, but it measures the glycation of albumin rather than hemoglobin.

9/15/09 4:40pm

Thanks, Gretchen, I will ask for that. Can I trust the readings I am getting at home from my glucose monitor?

9/16/09 8:17am

I don't see why not. You're measuring glucose, not hemoglobin.

4/12/10 8:17am

My A1C's have always been higher than my meter averages show. My endo seems to believe that it could be a result of the lifespan of my RBC's. Is there any test that can tell us if this is true? Also, can my endo test for iron deficiency? Thank you.

Anonymous
Pink rose
1/19/11 9:02am

I have mild anaemia but am not iron deficient as such. How would this impact my A1c reading?

1/19/11 7:38pm

Anything that affects the lifetime of your red blood cells will affect your A1c. Ask your doctor what kind of anemia you have and how that will affect red blood cell lifetime.

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