Hba1c, libre and red blood cell survival

Ica291

Well-Known Member
Messages
48
Type of diabetes
Type 1
Hello,

Off coronavirus topic.....

For the past 2 years my hba1c has been different to my libre estimated a1c by around 5 or 6. Which is quite a lot. Whilst pregnant it was out by 12 (estimated 48 but was 60 on test). When I asked my nurse about it, she told me that anemia will give a false hba1c and to go with the libre. She said the libre is a much better way of knowing what your sugars are doing and not an hba1c.

I have just had my hba1c come out at 66, while libre is estimating 50.

I have searched and searched for reliability of the tests and the libre. Libres are calibrated before they come out and considered very accurate. Hba1cs are considered accurate within 0.5%...... I'm so confused.

Finger picks show accuracy on my libre.

I'm wondering if the survival rate of my rbc has come into it. A few weeks ago I had a particularly stressful time and sugars were high for a good couple weeks. Until my fight or flight wore off, I couldn't get them down. But now they are back to being in range 75% of the time.

I had my hba1c test directly after this stressful episode, so I was expecting a higher reading, but not that high. So I'm wondering if the rbc that were tested were only a month old at most and that explains the higher hba1c than I was expecting.

Which leads to my next question. What would cause my rbc to not live a 3 month cycle?

Anyone got any super knowledge on this?!

Thanks x
 

barrym

Well-Known Member
Messages
801
Type of diabetes
LADA
Treatment type
Insulin
I wouldn't worry about HbA1c. It's modern tech trying to match an out dated test based on a glorified aged average. Ok when we had nothing better. But now we've got Time in Target. That's what you want to take note of (providing your Libre gives you good reliable readings). My consultant goes straight to that now.

HTH
 
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Ica291

Well-Known Member
Messages
48
Type of diabetes
Type 1
I wouldn't worry about HbA1c. It's modern tech trying to match an out dated test based on a glorified aged average. Ok when we had nothing better. But now we've got Time in Target. That's what you want to take note of (providing your Libre gives you good reliable readings). My consultant goes straight to that now.

HTH

Thank you

That does help
 

EllieM

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@lca291, your doctor probably won't want to do it, but a fructosamine test can also be used to gauge blood sugar levels. (They tend to give them to pregnant women because they average over the last 2 or 3 weeks). Hba1cs just don't work for some, but as long as your doctor realises this and accepts your (more accurate) blood sugar readings, does it really matter?
 

Ica291

Well-Known Member
Messages
48
Type of diabetes
Type 1
@lca291, your doctor probably won't want to do it, but a fructosamine test can also be used to gauge blood sugar levels. (They tend to give them to pregnant women because they average over the last 2 or 3 weeks). Hba1cs just don't work for some, but as long as your doctor realises this and accepts your (more accurate) blood sugar readings, does it really matter?
Thank you!
 

Brunneria

Guru
Retired Moderator
Messages
21,889
Type of diabetes
Type 2
Treatment type
Diet only
If the HbA1c is considered to be accurate within 0.5% then that equates to around 5.5mmol/mol

my own HbA1cs always equate to an average bg reading of around 7mmol/l (6% or 42mmol/mol) whereas my Libre, calibrated with the miaomiao and prick tests puts my average reading under 6mmol/l (around 5.3% or early 30s mmol/mol)

I’m far more interested in my standard deviation and time in target. I view the HbA1c as something my nurse does to tick a box on her screen. It serves no useful purpose for me and my bg control (which I work very hard at).

1F25E0C8-02BD-4AF7-962B-162105F1F3DA.jpeg
 

Bluetit1802

Legend
Messages
25,216
Type of diabetes
Type 2 (in remission!)
Treatment type
Diet only
For some people the HbA1c is not a reliable marker. I am another that sees higher HbA1cs than my Libres and finger pricks tell me - by a significant amount. My GP understands this. She arranged for me to have my HbA1c tested by 2 different labs from the same blood draw. (These 2 labs use different types of testing machinery). Twice now, these double tests have come back with a difference of 4mmol/mol from same blood draw.

The thing that concerns me with all this is that the HbA1c is just as likely to be lower than expected, which may lead people into a sense of false security.

It can also make a difference when the first diagnosis is given - how many are diagnosed with T2 when they may not be T2, and how many are undiagnosed when they have T2.
 

Resurgam

Expert
Messages
9,850
Type of diabetes
Type 2 (in remission!)
Treatment type
Diet only
My Hba1c indicates an average BG level which is about my maximum actual reading - even when I reduced my carbs the Hba1c did not alter so I am fairly certain that the assumed relationship between the two testing methods is not always accurate.