This is the name given to the finger prick blood test that you do each time you come to clinic. It shows you what your blood glucose control has been over the past 2-3 months.
Haemoglobin is part of the red blood cell and carries oxygen to the cells in the body. During the lifetime of a red blood cell (approx. 120 days) glucose flowing in the blood sticks to the haemoglobin.
HbA1c is a measure of the percentage of glucose that has bound itself to the haemoglobin in the red blood cells. Therefore the more glucose that is in the blood, the more haemoglobin will stick to it. This will result in a high HbA1c result.
The red blood cells are slowly being replaced all the time and the HbA1c will therefore show how much glucose has been flowing in the blood stream on average for the past 8-12 weeks. This will change every couple of months, and so needs repeating each time you attend clinic.
If your blood glucose levels are mostly high, your HbA1c will be high.
NICE (2015) guidance recommends aiming for a HbA1c of 48mmol/mol (6.5%). You will achieve this if most of your blood glucose values are between 4-7mmol/l.