Glycosylated (glycated) haemoglobin is a blood protein combined with glucose (sugar). Normally it is 4-6% of normal haemoglobin. When sugar exceeds the tolerance level for a long period of time (6-8 weeks) it is bound to haemoglobin. Consequently, this laboratory indicator shows the level of glucose elevation over the previous month and a half.

The test is necessary for diagnosing diabetes mellitus and monitoring the progression of the patient with this disease.

By measuring the concentration of glucose in the blood, you can see the condition of the body at the time of testing, while glycated haemoglobin shows the doctor the patient's health for the whole month. The period depends on the life span of the red blood cells, averaging up to 120 days. It is possible that a person may have a short-term elevation of glucose values for any reason (failure to follow a diet on the eve of blood donation, stressful condition...).

In the treatment of diabetes, the target level is a decrease in glycosylated haemoglobin of less than 7%.