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Libre HbA1c v Actual HbA1c

rebrascora said:
That is an interesting point and may explain some of the variability in prediction differences if each prediction is only based on the 2 weeks of data for each AGP period.
Click to expand...
Just to clarify further to this the 90 day data I was referring to was the libre link app in the estimated hba1c section not libre view
 
Thanks for the clarification @digihat and @rebrascora. If anybody else can contribute then it would be good to indicate whether they were reporting Libre view or Libre app predictions.
 
If I was to chime in. I get prediction from Librelink & a logging app I’ve used for BGs. Over many years. From my observation, both app interpretation's are pretty close. & both are 15% higher than the official blood test. (When I get it done once a year.)
 
Thanks for the clarification - I'm not a libre user and quite happy to be put right when my lack of direct knowledge shows.

If anybody has any more numerical comparisons and can chip then in it would be helpful. Not enough data yet to make any usable observations.
 
Dexcom user here and my prediction was 48 and I got blood test result of 52

And a perfect set at the time of having literally the same 7,14, 30 and 90 readings
 
There are two formulas use to estimate HbA1c from CGM data - eA1c and GMI. GMI is the newer formula and is thought to be more accurate so long as the CGM data is accurate (on average). In the Libre 2 app you'll see eA1c, and on the LibreView site you'll see GMI. In LibreView you can specify the date range for the 'blood glucose report', which influences the GMI figure displayed on that report. The app appears to use data stored in the app itself going back up to 90 days, deleted with the app is uninstalled. Both formulas use average blood glucose level over a period of time to estimate HbA1c.

There's an eA1c calculator on this page:

HbA1c Calculator

www.hba1cnet.com www.hba1cnet.com

And a GMI calculator on this page:

Glucose Management Indicator (GMI) | JCHR

www.jaeb.org www.jaeb.org

On either page enter the average BG value and it will provide an estimated HbA1c, which assumes that average BG level in the months leading up to a HbA1c blood test and a typical turnover rate of red blood cells.
 
My last one was 33 on Libre and with bloods 38. I always have this difference.
 
My last blood HbA1c was 54 and the Libre estimate with 90 days data was 45. So not very accurate for me.
 
Two more added

Libre Actual Difference
45 47 -2
51 47 4
41 39 2
35 45 -10
38 47 -9
48 46 2
39 44 -5
48 56 -8
46 58 -12
33 38 -5
45 54 -9

Bit of a pattern emerging. Any more?
 
Some pretty good numbers there!
 
I used libre before my last blood test, where I'd stopped the metformin.
The result was 37, libre predicted 34. (The previous blood test with 500mg of Metformin was 38)
 
Docb said:
This is brilliant. @helli - I've no idea how the libre does its estimating but if you don't enter any real results for it to fine tune predictions for any individual I reckon they must use a standard algorithm for everybody.

Libre Actual Difference
45 47 -2
51 47 4
41 39 2
35 45 -10
38 47 -9
48 46 2
39 44 -5
48 56 -8
46 58 -12

This is beginning to look interesting. Seems to be a bias towards underestimating, sometimes by quite a lot. Could do with more data. Any offers? Historic stuff would be OK.
Click to expand...
I've just fired up the laptop to upload my latest results from my Libre reader, so while I was on Libreview, I changed the report parameters, to 90 days prior to the date I had my HbA1c blood test back in December.
It changed the estimate (or Glucose Management Indicator, as they now call it) to 47, which was exactly what my HbA1c said!
 
Another added

Libre Actual Difference
45 47 -2
51 47 4
41 39 2
35 45 -10
38 47 -9
48 46 2
39 44 -5
48 56 -8
46 58 -12
33 38 -5
45 54 -9
34 37 -3

9 under estimates, 3 overestimates. Interesting. Any more?
 
Docb said:
Libre Actual Difference
45 47 -2
51 47 4
41 39 2
35 45 -10
38 47 -9
48 46 2
39 44 -5
48 56 -8
46 58 -12
33 38 -5
45 54 -9
34 37 -3
Click to expand...
Interesting that these are all relatively low HBA1c results for people on a diabetes forum with only 25% of the actual results within the type 2* diabetes range of 48 or higher.
It could be interesting to see some comparisons from higher results, especially as CGMs have a tendency to over-egg high BG.

*With my HBA1c results, I notice the same range used but I do not think it makes sense for someone with Type 1 as we can only achieve this with insulin so we will never be in remission.
 
helli said:
*With my HBA1c results, I notice the same range used but I do not think it makes sense for someone with Type 1 as we can only achieve this with insulin so we will never be in remission.
Click to expand...
I do get annoyed when I read my results online, and my HbA1c of 47 or 48 or thereabouts is marked with a large red 'Abnormal'
 
1738612798081.png
Saw this on Twitter/X (whatever you call it these days) earlier and that data is from Libre - even given the variables in Libre Data and actual blood results there is no way their HbA1c is 58+!!! I know there are other factors but 6.1% is less than my latest blood result and I'm told "no way Jose" to HCL - makes me think of a song "Someones knocking on the door, someones ringing the bell..."
 
mashedupmatt said:
View attachment 33848
Saw this on Twitter/X (whatever you call it these days) earlier and that data is from Libre - even given the variables in Libre Data and actual blood results there is no way their HbA1c is 58+!!! I know there are other factors but 6.1% is less than my latest blood result and I'm told "no way Jose" to HCL - makes me think of a song "Someones knocking on the door, someones ringing the bell..."
Click to expand...
Dispite the soothing voices assuring a 5 year roll out. (4 now? After the initial “fanfare.”) I can’t help a certain post on formerly Twitter reposted is a little bit overly optimistic riding “high on the hog” after the Libres. Lol, I’m told by my lot they can’t get the staff? Of course there will also be more T1s diagnosed every year.
 
Satan’s little helper said:
Dispite the soothing voices assuring a 5 year roll out. (4 now? After the initial “fanfare.”) I can’t help a certain post on formerly Twitter reposted is a little bit overly optimistic riding “high on the hog” after the Libres. Lol, I’m told by my lot they can’t get the staff? Of course there will also be more T1s diagnosed every year.
Click to expand...
Have my next DSN review appt at the end of the month (never seen a consultant) - let's see what they say... I'm not holding my breath
 
mashedupmatt said:
Have my next DSN review appt at the end of the month (never seen a consultant) - let's see what they say... I'm not holding my breath
Click to expand...
My consultant is like a tired middle manager just biding his time to a well “deserved” early retirement? Good luck with your DSN. Mine ain’t too impressed with my consultant either. (Let’s just say they don’t leap to his defence when I voice my opinion, they tend to chuckle in agreement.) I got a “commendable” HbA1c. But according to my consultant. “You don’t seem to get hypos.” As he looks at 90 day “daily patterns” on librelink off my phone. I’ve offered to let the guy shadow me for a week at work. But I don’t reckon he could actually keep up with me on the shop floor?
 
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