Changes in HbA1c value reporting
At the April Group meeting Dr Ghandi gave a presentation on blood glucose testing. He told us something about the history, going back to the 1970.s when the links between blood glucose control and developing complications in diabetes were not understood. There were no satisfactory means of carrying out long term measurements of blood glucose. It was in the late 1960's when an Iranian born doctor, Samuel Rahbar, noticed abnormal forms of haemoglobin in patients with diabetes and this led to the development of the HbA1c tests. At first there was no standardisation of these tests but then by 1996 a worldwide certification system had been set up.
HbA1c results have been given as a percentage, but this is now changing to a new measurement to be used worldwide and will be reported as mmol/mol.
The HbA1c measures the amount of glucose that is being carried by the red blood cells in the body and gives an idea of the level of blood glucose from the previous 2 -3 months. The results are used to make decisions about an individual's diabetes treatments. Any reduction in HbA1c levels will benefit health and it is generally recommended to aim for a level of 7% (53 mmol/mol) in order to reduce the risk of diabetes affecting nerves, eyes, kidneys and heart. However everyone should discuss their own personal target with their diabetes care team.
From the HbA1c result it is possible to work out what average blood glucose levels are running at day to day. This is the estimated Average Glucose (eAG) and the results are given in units like those given by blood glucose monitors.
The table below shows the estimated average glucose level (eAG) for different HbA1c levels and shows the equivalent readings in the new measurement method.
| HbA1c | eAG | New HbA1c |
| 6% | 7.0 | 42 |
| 6.5% | 7.8 | 48 |
| 7% | 8.6 | 53 |
| 7.5% | 9.4 | 59 |
| 8% | 10.1 | 64 |
| 8.5% | 10.9 | 69 |
| 9% | 11.8 | 75 |
| 9.5% | 12.6 | 80 |
| 10% | 13.4 | 86 |