In medical practice, there are frequent cases when it is difficult to evaluate the effectiveness of sugar-lowering drugs and the adequacy of the prescribed treatment in patients with diabetes mellitus. It seems that a person feels satisfactory, and his fasting glucose is within normal limits, but what is the likelihood of complications in this patient? After all, the amount of glucose in the blood is estimated only at the time of the study, this indicator is single.
Sometimes, an increase
in blood glucose occurs in healthy people, for example, after taking a large amount of carbohydrates or with excessive mental and emotional stress. The intake of certain medications, such as oral contraceptives, some diuretics,
psychotropic drugs, can also affect sugar levels
. In all difficult cases, the endocrinologist comes to the aid of analysis for glycated hemoglobin, in the direction of the study it is designated as HbA1c.
Glycated hemoglobin is the resultant combination of glucose and hemoglobin A molecules, normally this process occurs continuously in healthy people. The amount of hemoglobin subjected to glycation is 5-8%. In patients with diabetes, this indicator increases by 2-3 times and persists throughout the life of the red blood cell, i.e. 120 days. Since both young and mature red bodies are present in the blood, the average age of the red blood cell is taken, which is equal to the half-life of it - 60 days.
Glycated
hemoglobin, the norm of which is 4-6.1% of the total hemoglobin level, shows the average glucose content for two months until the blood test is taken. Therefore, it can be determined whether there was a long-term increase in glucose or within 2 months this indicator was in a normal state. The correlation between HbA1c and blood glucose was proved by many years of research, empirically it was found that an increase in blood glucose by 1.59 mmol / L corresponds to 1% of glycated hemoglobin.
When is a glycated hemoglobin test prescribed?
- for the diagnosis of diabetes and the level of compensation;
- to control the treatment with hypoglycemic drugs ;
- to determine the risk of vascular complications in diabetes;
- in all cases of impaired glucose tolerance and diagnosis of prediabetes;
- pregnant women at risk of developing diabetes.
Interpretation of diabetes test results:
Up to 5.8% - diabetes is well compensated.
From 8 to 10% - partially compensated diabetes.
Over 12% is a poorly compensated disease.
Endocrinologists try to select therapy so that the glycated hemoglobin is in the range from 7 to 8%. With adequate treatment, elevated HbA1c levels return to normal one month after the adjustment.
The American Diabetes Association advises that research be done at least every 6 months. In Russia, an HbA1c analysis is prescribed to all patients receiving insulin and sugar-lowering drugs once every 3 months. By the level of HbA1c hemoglobin, one can judge whether the patient is likely to develop pathology of the microvasculature of the retina, kidneys and damage to nerve fibers.
In what cases are possible distortions of the analysis on HbA1c?
A false increase in the results is observed with an increase in the level of fetal hemoglobin in the blood and with iron deficiency anemia. A false decrease in indicators is detected during the destruction of red blood cells due to hemolysis, after a blood transfusion or massive blood loss.
A glycated hemoglobin test is prescribed a little more often (1 time per month) to patients who have a non-standard course of the disease, if they have a severe comorbidity, to pregnant women with diabetes to prevent the development of pathology in the fetus.