Change to reporting of patients' HbA1c
From 1 October 2011 the way in which HbA1c results are expressed in the UK has changed. Results are now reported in the IFCC reference method of mmol/mol, rather than the DCCT units as a percentage. This follows a two-year transitional period, during which both reporting methods were used.
How do old and new relate?
Guide to the new values expressed as mmol/mol
| DCCT- HbA1c |
IFCC-HbA1c |
| (%) |
(mmol/mol) |
| 6.0 |
42 |
| 6.5 |
48 |
| 7.0 |
53 |
| 7.5 |
58 |
| 8.0 |
64 |
| 9.0 |
75 |
What are the recommended targets for people with diabetes in new units?
The equivalent of the current DCCT HbA1c targets of 6.5% and 7.5% are therefore 48mmol/mol and 58mmol/mol in the new units, with the non-diabetic reference range of 4.0% to 6.0% being 20mmol/mol to 42mmol/mol.
How is it calculated?
When HbA1c results are expressed as % haemoglobin, the equation describing the relationship is:
IFCC-HbA1c (mmol/mol) = [DCCT-HbA1c (%) - 2.15] x 10.929
Use our HbA1c converter to work out new values
To help people during this period of change, Diabetes UK developed an easy-to-use online HbA1c converter:
Convert HbA1c % to mmol/mol and vice versa
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Further information
For the complete background and further information on HbA1c please download our HbA1c factsheet (PDF, 185KB).