Numerous organizations support the ICFF method to report HA1c over the DCCT method. Most of Europe and UK use ICFF now. It's a good standard. Easy to work with and understand.
Typically HA1c values will be between 30 and 100. Really nice numbers are in the 40's. The lower the better, of course, just like with the DCCT method. It's probably difficult for non-US people to imagine that this method looks strange to most people in US. It's just a matter of what one is familiar with.
Conversion between DCCT and IFCC is by the following equation:
IFCC-HbA1c (mmol/mol) = 11 x [DCCT-HbA1c (%) - 2.15], and then round off with no decimal place needed. The final value doesn't need more than two significant figures for most people in ordinary use.
Example. My HA1c on my last blood labs was 7.0% given in the DCCT dimension. So this works out using the above formula to equal 53 in the ICFF method. Actually, my paperwork from routine ordinary blood labs (done at Quest Diagnostics, a big chain) prints both methods.
You ready for the change?
Your A1c was 7.0% which means that when your sample was drawn 7% of your blood cells contained glaciated hemoglobin there is really nothing to convert. The test is not an average of your blood sugar but doctors and some individuals like to convert this number into a blood sugar average. Most none PWD's walk around with about 5% glaciated hemoglobin and "us" PWD's can run anywhere between 5% and 25% and most of us would like to be closer to 5% than 25% and today most Endo's would like to say it's safe at or below 6.5%.....The rules could change again tomorrow.
When will I fly to work in my jetpants instead of having to drive my hovercar?
Or how come when I go to Home Depot I'm still buying 2x4 lumber instead of 3.81cm x 8.89cm lumber? Didn't we switch to the metric system under President Carter?
I agree that standardizing A1C is important but I don't think that US labs have even succesfully standardized on the DCCT method yet. If I get A1C's run at two different labs (local Quest and Labcorp) the results are off from each other by 1% in A1C (e.g. LabCorp got me a 5.4%, and Quest got me a 6.5%. Their reference ranges are even off from each other by a whole percent so maybe I shouldn't be surprised.).
Math and science aren't getting more popular in the USA so I don't see anything like this happening any time soon. It would cost money to change and reeducate people and there's not enough money available for this type of project which, in turn, means there's very little motivation. To me the biggest problems are BG targets and test strip availability and motivation to use them and I think there's a lot more ground to be gained there.
UTSW has been doing a long range A1c study and I think at some point there will be a new standard test. They recognize that every lab comes up with diffrent results. They test my A1c in their Hospital lab and again with a diffrent proses that is very accurate but to costly for mainstream use...my standard lab never matches the study lab results. The best solution at the moment is to just use the same lab.They have been retesting my A1c for about 5 years now but have not published any official results. I don't think any of my tests have been off by 1% more like .6 and I have been tested at Quest, labcorp, Mayo, and UTSW.