From April next year, HbA1c results will be reported in mmol/mol, giving a numerically larger result than the percentage level currently used. Results of 31, 42, 53 and 64 mmol/mol are equivalent to results of 5, 6, 7 and 8 per cent.
For two years, laboratories will give results in both percentage terms and the mmol/mol score, but from April 2011, results will only be given in mmol/mol.
Diabetes UK is developing three leaflets to explain the change to consultants and GPs, other health professionals and patients with diabetes. These will be sent out in 2009.
The units for reporting HbA1c results are changing following international agreement to use the International Federation of Clinical Chemistry standard. This gives results, in percentage terms, 1.5 to 2 per cent lower than the Diabetes Control and Complications Trial reference previously used by UK labs.
In January, a UK consensus group decided that new units should be used to avoid potential confusion because patients might assume their control had improved when, in fact, they were comparing their new results with old targets. A decision was therefore taken to express results in mmol/mol.
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