This leaflet is to help you understand what we mean by "HbA1c or glycated haemoglobin".  This is used as a very good guide to what your blood glucose levels are like

What does it measure?

Haemoglobin is present in everyone's red cell (the Hb of HbA1c), this is what makes your blood red.  Glucose sticks to red cells and the more glucose there is around them the more glucose is attached for red cells (see diagram 1).  The average life span of a red cell is 120 days and therefore if we measure how many red cells have glucose attached to them, it gives us a guide to the glucose levels in your blood over the last 120 days.

What it does not measure?

This can be the confusing bit.  It is not a measure of blood glucose as you would get if you are doing a finger prick and testing your blood with a meter.  It does not measure sudden changes in your blood glucose.

What are normal levels and how does it relate to your blood glucose?

These can vary a little bit between laboratories but in Leeds when done in the laboratory, the normal (non diabetic) value is 4.0-6.5%.  This means that approximately up to 6 red cells out of every 100 in your blood will have glucose attached.

National guidelines are to have an HbA1c of less than 7.5%.  This is very tough and hard work to achieve but worth it.

How often is it measured?

We aim to measure it every time you come to clinic, about every 3 months.

Diagram 1 - Normal HbA1c

Diagram 2 - High HbA1c