Can Hba1c's be wrong?

[clairemm]

Does anybody have any experience of Hba1c's being wrong?

I was only diagnosed about 6 months ago on the back of a few interesting symptoms and a fasting bg of 15.

Since then I?ve had 2 hba1c's and the results of the first one surprised me! the improvement was so apparently so good (7.7) my dsn was waiting for me in the waiting room and full of shock and praise, I had tried hard and made quite a few changes and obviously was now on medication (4x metformin) but I was still surprised at how surprised she was, as if that wasn?t normal.

But since that one I slipped back into some bad habits, put on a bit of the 3 stone that I?d lost and generally just been naughty (and felt rubbish as a result unsurprisingly) so I really didn?t want to go for the results of my latest Hba1c yesterday coz I thought I?d get a right telling off ! yet the improvement was even better, 6.4 now ! Which is good news, but knowing what I know about what I?ve been doing does make me wonder if it?s actually accurate or basically all a waste of time.

Please don?t take this as a "I?m giving up" statement because I?m going to be an angel again now, purely because I feel so rubbish when I?m not behaving, but it has really made me question how accurate these tests are.

 

[Andy HB]

I guess the medication is doing its job then!

There is no reason to think that the HbA1c measurement is wrong. Take it as some good news and redouble your efforts to re-lose that gained weight, be a little less 'naughty' in future and look forward to an even better HbA1c!! 🙂

However, just remember that the HbA1c measure is just a guide. It doesn't tell the whole story. If you are going up and down like a yo-yo BG-wise, you aren't going to be doing yourself any favours in the long run even though HbA1c-wise your numbers are looking Ok!

You can also manipulate the HbA1c result by being really good in the last few weeks, because the result is heavily weighted on that basis. But, tbh, you'd have to be pretty stupid to do that wittingly (i.e. I guess everyone is subconciously guilty of that to some extent!!).

Andy 🙂

 

[Lizzzie]

I have a few reasons to be suspicious but no good evidence.

1) I once heard a DSN say that you can 'cheat' a bit by having a bad hypo in the day or two before the blood is taken: it biases it lower (I might have misunderstood this).

2) I'm also not sure that HbA1Cs between 2 different people are always that comparable: when I asked some friends for their typical day's readings, 7-day average blood glucose and HbA1Cs we were unconvinced about the consistency, but these were on different machines in different parts of the country too.

COnclude though that it's by far the best thing guide we've got and since so many studies seem to correlate a low HbA1c with fewer complications and Good Control, it's still definitely worth doing battle to keep it within good limits and well done for your good work.

Remember that your perceptions of how you're doing will change over time too and knowing my own self-evaluation, I know these are probably much more likely to be unreliable than the HbA1c number!! :0)

 

[Mark T]

The only thing that I thought could make them incorrect was if your blood iron levels were askew.

The test works by counting the glucose that has stuck to your red blood cells. Since your red blood cells die off and are replaced at a steady rate then they can take a guess about your average levels.

 

[clairemm]

Thanks for the replies.
I used to test, test, test all the time, my dsn gave me a monitor but after 2 prescription for a pack of strips in 2 months (i paid for the others myself) they refused to prescribe me anymore and i cant afford to keep paying the increasing prices. when i tried to work out my own hb1ac based on these readings and i was quite a bit out.
think i'm over thinking it all those. think i'll stick to sugar = bad. walking = good lol