What is HbA1c?
HbA1c gives an idea of what your blood glucose has been averaging over the last 3 months. Haemoglobin is found in red cells in the blood. Because haemoglobin is a protein, glucose will stick to it (it does this in all people, even those without diabetes). The more glucose there is in your blood, the higher the HbA1c will be.
Red blood cells live for only 3 months in the blood before they are replaced, so measuring how much glucose gets stuck tells us how much glucose has been around over those 3 months.
Does the glucose alter my haemoglobin?
No it does not alter what haemoglobin does, which is to take oxygen around the body.
How is a finger prick glucose level different?
You do finger prick tests at home to give you information about changing your insulin dose and stop you from going too high or too low. The result is measured in milimoles per litre (mmol/l). Whilst this is really important to tell you what your glucose level is at any given point of time, it will go up or down quite quickly.
HbA1c is an ‘average’ measure of your glucose level over a longer period of time. It provides us with accurate information about the risk of longer term problems with diabetes such as eye, kidney and nerve damage. The way that we report HbA1c has recently changed from percentages (the DCCT unit) to mmol/mol (the IFCC reference method).
Research tells us that young people with diabetes need to aim for an HbA1c of 58 mmol/mol (7.5%) or less.
The new HbA1c numbers sound like my Blood Glucose numbers – are they the same?
Whilst the numbers sound the same, they are different. Use the chart below to see how the HbA1c (%), compare to the HbA1c (mmol/mol) and your estimated average blood glucose level. Your average blood glucose level can be obtained from some of the different meters, so have a look to see what yours can do.
HbA1c % / HbA1c mmol/mol / Estimated average blood glucose mmol/L14.0 / 130 / 19.7
13.5 / 124 / 18.8
13.0 / 119 / 18.1
12.5 / 113 / 17.2
12.0 / 108 / 16.5
11.5 / 102 / 15.6
11.0 / 97 / 14.9
10.5 / 91 / 14.0
10.0 / 86 / 13.4
9.5 / 80 / 12.5
9.0 / 75 / 11.8
8.5 / 69 / 10.9
8.0 / 64 / 10.1
7.5 / 58 / 9.3
7.0 / 53 / 8.6
6.5 / 48 / 7.8
6.0 / 42 / 7.0
5.5 / 37 / 6.2
5.0 / 31 / 5.4
How often will my HbA1c be tested?
We will test your HbA1c every three months and this will be done when you come to the diabetes clinic. The test only takes 6 minutes so the results can be discussed with you, your family and the diabetes team.