To understand the level of blood glucose control in diabetic patients, it is important to monitor not only the blood glucose of each segment, but also a very important test – glycosylated hemoglobin (HbA1c). Why do diabetic patients need to measure glycated hemoglobin? Glycated hemoglobin (HbA1c) refers to hemoglobin that has been glycated by glucose. When glucose in the blood comes into contact with hemoglobin (i.e., hematocrit), the two cross-link together and slowly undergo irreversible glycation to form glycated hemoglobin. When the concentration of glucose in the blood is high, the level of HbA1c formed in the body is also relatively high. The life span of human red blood cells is generally speaking 120 days, and the level of HbA1c in the blood remains relatively unchanged until the death of the red blood cells. Thus, it seems that the level of HbA1c in the blood changes once every 120 days and is not affected by an occasional increase or decrease in blood glucose. The daily blood glucose measurements taken by diabetics only reflect the changes in blood glucose at the time of the test, while the HbA1c measurement gives a picture of overall blood glucose control over the past 2-3 months. However, recent studies show that 51% of people with diabetes have never heard of HbA1c, and more than 10% of physicians test their patients with HbA1c less than once a year. In China, only 1 in 4 physicians recognize it as an important measure of blood glucose control. Experts recommend that HbA1c measurement should be performed every three months. Normal value of glycosylated hemoglobin The current reference value of HbA1c in China is 4%-6%, and the “Chinese Diabetes Prevention and Control Guidelines” suggest that the control standard for diabetic patients is below is 6.5%. Studies have found that for every 1% increase in HbA1c, the risk of retinopathy progression increases by 33%. There was a correlation between HbA1c in early gestational diabetes and the incidence of congenital malformations in the fetus, with no malformations in HbA1c <6.9% and 22.4% in >8.5%. The UK Prospective Study of Diabetes (UKPDS) confirmed that for every 1% reduction in HbA1c, there was a 21% reduction in diabetes-related mortality; a 14% reduction in the incidence of myocardial infarction; a 12% reduction in the incidence of stroke; a 37% reduction in the incidence of microangiopathy; a 19% reduction in cataract extraction; a 43% reduction in amputation or mortality due to peripheral vascular disease; and a 16% reduction in the incidence of heart failure. Why is glycated hemoglobin the “gold standard” of blood glucose monitoring? –It can reflect the average blood glucose level in the previous 2-3 months, and judge the overall situation of blood glucose control. –It can determine whether the treatment plan is effective, and if it does not meet the standard, the plan should be improved. —It is a window to diagnose diabetes, observe the condition, predict the chance of complications, and provide a reliable basis for doctors’ treatment.