She shouldn't blame the Yanks for the new way of reporting HbA1cs As technology has changed scientists have become more able to give accurate results but were still calibrating machines according to the standards of 30 years ago ( DCCT HbA1c, based on the agreed standards used for a long term T1 diabetes trial, Diabetes control and complications trial)
Thirty years later we know a bit more about glycated haemoglobin and how much is really present than we did then . There is now a new international agreement on the calibration of HbA1c analysers (by members of the International Federation of Clinical Chemistry so IFCC) which reflects the new knowledge. .
After they agreed to change the calibration then it became clear that they also had to change the units to avoid confusion . If they had continued to use % with this new, more accurate calibration, HbA1c results would have appeared to be 1.5%-2% lower overnight! (a few years back I remember a person on a forum wondering why his HbA1c was now something like 4.1% which was far too low to be a realistic result. It turned out his country had changed to IFCC calibration. This was before the agreement to change units )
Different countries are adopting the new terms/calibration at different times so for a while some will be using the new system and some the old.
Some of the experts who use these figures all the time have looked for quick methods that can give rough conversion s quickly . These are both by British diabetologists/researchers.
Kilpatrick's Kludge
To change DCCT Hb A1c (ie % HbA1c) to IFCC HbA1c (ie mmol/mol)
minus 2, minus 2.
ie if the old figure was 8% take away 2 that makes it 6 in the tens column, take away 2 again and that gives 4 in the units column. DCCT HBa1c 8%= IFFCC 64 mmol/mol
This works for whole number percentages from 4-13%.
For non whole numbers then there's a more complicated method.
Middle's Manipulation
To change DCCT to IFCC multiply by 11 and subtract 24
so to change DCCT HbA1c 6.5% to the new IFCC
6.8x 11=74.8
71.5-24 = 50.8 rounded up to 51 mmol/mol
You can work this one the other way round
so to change IFCC to DCCT add 24 and divide by 11.
51+24= 77
75/11 = 6.8
http://www.idf.org/sites/default/files/ ... ohn_EN.pdf