HbA1c is a blood test used for measuring the effects of glucose on your body. In this short video, one of Australia’s leading authorities explains how it is used in diagnosing and monitoring diabetes type 2.
HbA1c measures the percentage of haemoglobin in your blood that has been affected by glucose. It is a particularly useful test because as it is reflecting the process of the more widespread tissue damage that is occurring. As you can imagine, if glucose sticks to proteins like haemoglobin, it is also sticking to other proteins in your body and causing damage. A good way of thinking about the effect of glucose on your body is to compare it with the way sugar becomes caramelised when heated - the sugar sticks together to make toffee. This is what happens when glucose sticks to haemoglobin.
When someone has a glucose test, this only shows the level of glucose in their blood which is present at that moment in time and the circumstances might mean that it is particularly high or low for a temporary reason. An HbA1c test shows the average glucose damage levels over the previous four months and therefore provides a much more even estimation of a person’s situation. The HbA1c test is not affected by diet or exercise and therefore you do not need to fast before giving a sample. Whether you're having your HbA1c test for the diagnosis of diabetes or to manage it, you don't need to have the test more than once every four months.