HbA1c | Glycosylated Hemoglobin

Glycosylated Hemoglobin (HbA1c) is a form of hemoglobin that forms when glucose molecules attach to erythrocyte hemoglobin. This process occurs irreversibly throughout the erythrocyte's lifespan (about 120 days), thus the HbA1c level in the blood reflects the average glucose concentration over the past 2–3 months. It is one of the most important and reliable indicators for the diagnosis and treatment control of diabetes (DM), expressed as a percentage of the total hemoglobin content.

The test is used both for diabetes diagnosis and for evaluating treatment effectiveness. A constant increase in HbA1c is associated with a high risk of cardiovascular complications, nephropathy, retinopathy, and neuropathy.

Principle of the test: HbA1c is determined by various methods, most commonly immunochemical, ion-exchange chromatography, or enzymatic methods. The results are presented as a percentage (%) and reflect the average glucose over several months.

Recommendations:

• Recommended to perform:

– For diabetes diagnosis, when HbA1c ≥ 6.5% (the diagnosis must be confirmed by a repeat test).

– For those with DM – every 3 months to assess glycemic control.

– When there is impaired glucose tolerance, HbA1c helps assess the prediabetic condition.

• Certain conditions can affect the interpretation of test results:

– Hemolytic anemia, recent blood transfusion, hemoglobinopathies – can decrease the HbA1c level.

– Long erythrocyte lifespan (e.g., iron deficiency anemia) can falsely increase HbA1c.

• No special preparation is required for the test – it can be performed at any time of the day, fasting or after a meal.