NZSSD Position Statement on standardisation of reporting units for HbA1c and application of estimated average glucose (eAG)

New Zealand (NZ) clinical laboratories should implement dual reporting of HbA1c in both molar units (mmol/mol) and currently reported DCCT-aligned units (%), as recommended in a consensus statement from ADA, EASD, IFCC and IDF, published in 2007. After a period of two years from the time of implementation it is envisaged that only molar units will be reported.

Although explicit times have been set in the United Kingdom (1 June 2009 for initiation of dual reporting and 1 June 2011 for reporting only molar units), it is most important that implementation is coordinated across NZ laboratories, ideally in synchrony with Australasia. The NZ clinical laboratory community should cooperate to achieve dual reporting in a standardised format.

There is some evidence in support of also reporting estimated average glucose (eAG), although this has not received universal endorsement. It is recommended that eAG may be used at the discretion of individual practitioners as an educational tool at the point of delivery of care to patients with diabetes. It is not recommended that eAG should appear on laboratory reports at the present time, although there should be flexibility to adopt this if a strong Australasian commitment emerges.

The above recommendations should be supported by educational tools and resources, which should be adapted to meet local requirements.

This position statement was written by Dr Chris Florkowski and Dr Michael Crooke and was endorsed by the NZSSD Executive on 20 February 2009.