HbA1c – also referred to as glycohemoglobin or glycated hemoglobin – is an important diagnostic long-term parameter in diabetes mellitus. Based on the HbA1c values, the average blood sugar level of the last eight to twelve weeks can be measured. Therefore, the term “blood sugar memory” is also often used.
The HbA1c value in healthy people is less than 5.7%, in the case of so–called prediabetes, the value is between 5.7 – 6.4%, the diagnosis of diabetes mellitus is made at an HbA1c value of 6.5% or more.
What is HbA1c and why is the long-term glucose value so important?
The HbA1c value indicates the percentage of hemoglobin associated with glucose and allows a retrospective assessment of the patient’s blood glucose control from the last eight to twelve weeks. The process of glycation/ saccharification of hemoglobin occurs without enzymes and is an irreversible reaction, which is canceled by the lifespan of red blood cells (100 – 120 days).
The starting product for the reaction is primarily the native, i.e. non-glycated / non-saccharified hemoglobin HbA0. As a result of the attachment of various carbohydrates to the β-chain of hemoglobin, HbA1 is formed, consisting of the following subfractions:
The essential c sub-fraction (HbA1c) is the largest fraction of HbA1 at 70 percent and serves as a so-called “blood sugar memory” or as a long-term blood sugar value and can be given as a percentage (percentage of glycation in total hemoglobin) or in mmol / mol Hb. The more hemoglobin has been glycated/saccharified, the higher the value. The reference range is less than 5.7 percent, which means that less than 5.7 percent of hemoglobin is saccharified. The determination of the HbA1c value is of great importance both in the diagnosis and in the monitoring of the course of therapy of diabetes mellitus.
When is the long-term glucose level measured?
If diabetes mellitus is already present, the measurement of the HbA1c value once a quarter is recommended in addition to the additional blood sugar control. Compared to a fasting blood sugar measurement, which is only a snapshot of the blood sugar level at the time when you measure the blood sugar in the morning before the first meal, the measurement should be considered as a longer-term measurement. No preparation of the patient is required for the measurement.
What is normal A1C level?
How can I lower my A1C quickly?
What is the difference between A1C and blood sugar?
What causes high A1C?