Hba1c doesn't match blood tests

[Krystyna23040]

Has anyone else ever had this. My Hba1c this time is 42 but the last three months before meals and fasting my own tests were 4.0 to 5.5. 2hrs after meals no higher than 6.8 and by 3 hours back down to fasting (I usually only eat 2 meals a day). Exactly the same thing happened with my last Hba1c of 44. When I used the freestyle libra it was exactly the same. My libra would predict Hb1ac of 37 but I would be in the 40s.

I checked my meter against another that I have and the readings are very similar. I am not unduly concerned because it means I still stay off the meds but I am intrigued as to why it is happening.

 

[Knikki]

I would not trust the Libre reader or app to work out what my Hb1Ac is (it always tells me I'm 34 which is rubbish) , it is just an algorithm based on a average figure and can't compare to the accuracy of a lab result.

 

[Krystyna23040]

I would not trust the Libre reader or app to work out what my Hb1Ac is (it always tells me I'm 34 which is rubbish) , it is just an algorithm based on a average figure and can't compare to the accuracy of a lab result.

Yes - I do agree that the libre reader was too optimistic with its working out. But am still a bit puzzled why - after being so good with my carbs and getting good readings for hours on end - how my Hb1ac is so high compared to blood sugars.

 

[Knikki]

Arh! well now you need to question "how accurate is the Libre?".

Have you compared your Libre reading with finger pricks?

Im sure you know how Libre works but as a rough guide they can be out by one point or more (know doubt some will be along in a minute and go "mine is very accurate blah blah blah) or sometimes more.

For example last Saturday Libre was saying 7.5 and level however I really did not feel right so did a blood test and was 17.2. Now that is a bit of an extreme and even in all the time have been using it, had not see it that far out.

There are many reasons why the Libre on your arm may or may not be accurate but I would certainly just double check that what you see on the Libre corresponds with finger pricks

However not being a T2 I can't offer anymore in site as to why your Hb1Ac is not what you expect, sorry.

 

[mahola]

42 is great! Well done. HbA1c is calculated as an average over the previous 3 months. Your finger prick results probably would match up if you'd taken a reading every minute of every day... Your finger pricks are just a glimpse in time as to what your BGL is doing.

 

[Krystyna23040]

Arh! well now you need to question "how accurate is the Libre?".

Have you compared your Libre reading with finger pricks?

Im sure you know how Libre works but as a rough guide they can be out by one point or more (know doubt some will be along in a minute and go "mine is very accurate blah blah blah) or sometimes more.

For example last Saturday Libre was saying 7.5 and level however I really did not feel right so did a blood test and was 17.2. Now that is a bit of an extreme and even in all the time have been using it, had not see it that far out.

There are many reasons why the Libre on your arm may or may not be accurate but I would certainly just double check that what you see on the Libre corresponds with finger pricks

However not being a T2 I can't offer anymore in site as to why your Hb1Ac is not what you expect, sorry.

I do apologise for my confusing post. It made sense to me when I typed it - but reading it again I realised that it was very confusing.
I stopped using the Libre when I came off the insulin a year ago. All the readings since then have been with my Aviva Expert or the GlucoRX Nexus meters. I only mentioned it because when I was typing my post I remembered that the predicted Hba1c was always much lower than the real one.

 

[Krystyna23040]

42 is great! Well done. HbA1c is calculated as an average over the previous 3 months. Your finger prick results probably would match up if you'd taken a reading every minute of every day... Your finger pricks are just a glimpse in time as to what your BGL is doing.

Actually - you are right. My Hb1ac was 125 on diagnosis so I should be really happy with 42. I think I am trying for perfection and would love a 39.

 

[mahola]

Actually - you are right. My Hb1ac was 125 on diagnosis so I should be really happy with 42. I think I am trying for perfection and would love a 39.

So would I! My daughter's HbA1c was 38 three months ago and I was very jealous

 

[Knikki]

@Krystyna23040 No worries but a Hb1Ac of 42 is a great number and what ever you are doing is working

I still have no idea on the Libre

 

[Rustytypin]

Hi @Krystyna23040 ,I have had a similar problem, my predicted a1c is always lower than my actual lab results by 2 or 3 mol. I don’t know the reason and it seems to be something that a number of people have found. Frustrating I know. One predicted result was 34, lab result, in the 40s! The only thing I can think of, I have DP of around 6 to 6.5, and if it is that high for a long time overnight it could affect the a1c.

 

[DCUKMod]

@Krystyna23040 - I was diagnosed in October 2013. I have never, ever, ever had an A1c result match or close to my meter's prediction and yet further still adrift from the Libre. Indeed the Libre usually predicts c10 lower than the lab results return.

To be honest, I now separate the two things in my head. I look at the trends on my meter, and watch for them creeping either way, and play A1c lottery.

Please don't get me wrong, my numbers are good, with my last A1c lab result coming in at 4.6/27 a couple of weeks ago, but it is frustrating nonetheless.

Separating the results in my head helped me a lot, in dumping the "Eh?" Feeling at lab time.

Well done on the good score.

 

[Krystyna23040]

Hi @Rustypin - It's good to know that there is likely to be a logical explanation for it and that I am not the only person this is happening to.

@DCUKMod - that's very good advice. I will separate the two things in my head also and will stop trying to work out why the hba1c isn't as low as the meter seems to be suggesting it should be.

I can actually see now that there is a correlation between my meter and the hba1c. My meter readings have been consistently lower and my Hba1c has dropped from 44 to 42 so they are both showing better control.

 

[DCUKMod]

Hi @Rustypin - It's good to know that there is likely to be a logical explanation for it and that I am not the only person this is happening to.

@DCUKMod - that's very good advice. I will separate the two things in my head also and will stop trying to work out why the hba1c isn't as low as the meter seems to be suggesting it should be.

I can actually see now that there is a correlation between my meter and the hba1c. My meter readings have been consistently lower and my Hba1c has dropped from 44 to 42 so they are both showing better control.

In the early days I too found it mega frustrating, but that's how I got over it. We're not alone in this. I know of a few people in the same frustrating place.

 

[Bluetit1802]

Welcome to my club @Krystyna23040

Over the last 4 years my HbA1c has been several points over where my other data has indicated. The several points can be as many as 8. I have also done home A1c tests (available on line) on the same day as my official tests, resulting in a level virtually the same as my finger prick data and a little higher than the Libre. I know my Libres read low but I work out how low and mentally add this difference to the results.

It is common medical knowledge that the HbA1c can be skewed when someone has non-standard red blood cells or certain other medical issues. People with iron issues or anaemia or certain thyroid problems can be affected, as can anyone whose red blood cells do not live for the average 120 days that the HbA1c works on. If our RBC live longer than the 120 days the HbA1c can be falsely high - and vice versa. As we have no idea how long our RBC live, we have no way of knowing if that is the cause of our elevated HbA1c.

There are many papers on this subject if you care to Google.

 

[Krystyna23040]

Welcome to my club @Krystyna23040

Over the last 4 years my HbA1c has been several points over where my other data has indicated. The several points can be as many as 8. I have also done home A1c tests (available on line) on the same day as my official tests, resulting in a level virtually the same as my finger prick data and a little higher than the Libre. I know my Libres read low but I work out how low and mentally add this difference to the results.

It is common medical knowledge that the HbA1c can be skewed when someone has non-standard red blood cells or certain other medical issues. People with iron issues or anaemia or certain thyroid problems can be affected, as can anyone whose red blood cells do not live for the average 120 days that the HbA1c works on. If our RBC live longer than the 120 days the HbA1c can be falsely high - and vice versa. As we have no idea how long our RBC live, we have no way of knowing if that is the cause of our elevated HbA1c.

There are many papers on this subject if you care to Google.

Thank you - this is very interesting information. I will mention this to my DN on my review on Friday - in case I need more blood tests to rule out iron issues or anaemia. My thyroid was absolutely in normal range.

If it is a case that it is my blood cells living longer it will be something I have to live with. I am so pleased I posted because I feel so much better knowing I am not the only person this has happened to.

I googled it and read some info from Chris Kresser who said that if our blood sugars are running high our blood cells have much shorter lives. This makes sense because there was not this large discrepancy when I was on insulin and my blood sugars were running high. The discrepencies started when I got my BS under control with low carb/keto.