The haemoglobin A1c test gives an indication of how well your diabetes is controlled. The HbA1c test, also known as the haemoglobin A1c or glycated haemoglobin test, is an important blood test that gives a good indication of how well your diabetes is being controlled.Together with the fasting plasma glucose test, the HbA1c test is one of the main ways in which type 2 diabetes is diagnosed.he haemoglobin A1c test gives an indication of how well your diabetes is controlled. The HbA1c test, also known as the haemoglobin A1c or glycated haemoglobin test, is an important blood test that gives a good indication of how well your diabetes is being controlled.