I recently moved and changed endo’s. My previous doc used a device in the office to get an “instant” (about 10 minutes) A1C reading from a fingerstick. He also has A1C tests done by a lab as part of other bloodwork (from the vein). My new endo only has me go to a lab to have A1C tests done. When I was in pediatrics (1981-1990) my doctor not only had me go to a lab, which was the only option at the time, but said to always go to the SAME lab because of fluctuations between the two.
My perception is that the A1C done by a lab from the vein can be higher, by about 0.3 to 0.5. Since my new doc has always given me results over 7.0, while the previous one always gave me results under 7.0, it’s a bit disconcerting. (Fortunately, I got my life insurance based on the fingerstick, sub-7 numbers!)
Is there a noted, documented variation between the two? Does one test have more of a tolerance than another (meaning: if two tests were done within 5 minutes of each other, how difference would they be?)