HbA1c

HbA1c measures the share of haemoglobin in your red blood cells that has sugar attached. Because red cells live for a few months, the result reflects your average blood sugar over roughly the last two to three months rather than a single moment.

Doctors use HbA1c, alongside other tests, to diagnose prediabetes and diabetes and to see how well diabetes is controlled. The result is reported as a percentage or in mmol/mol, and your clinician uses set cut-offs to interpret it.

Some conditions can make HbA1c less reliable, including anaemia, some inherited blood conditions and recent blood loss or transfusion. If your result is outside the range, or you are unsure what it means, speak to your doctor about the next steps.