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A1C way off with Libre vs Blood test

S

Scorpio73

Newbie
Messages
1
Type of diabetes
Type 2
Treatment type
Insulin
Just got my A1C test results was tracking with my Libre GMI at 7.4, when I did my bloodwork it was 8.4. Am surprised that there was such a big difference. My last A1C was in Oct 2024 was at 7.6. I am flabergasted and don’t understand the discrepancy.
 

I'm not on any meds, but for me the Libre's suggestions for A1c results are always way off for me - aroun 10mmol/L or 1%,.
 
There's always some inaccuracy with testing. For example, fingerprick testing has an allowable inaccuracy of 15%, 95% of the time. A true value of 6.0 could therefore be shown as anywhere from 5.1 to 6.9. One in twenty results could be even further out.

Also, fingerprick testing and CGMs are testing different things - one is interstitial fluid, the other is capilliary blood. The CGM algorithm is supposed to adjust for that but it might not always get it right.
 
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