What Is Glycosylated Hemoglobin?

Glycosylated hemoglobin, English name Glycosylated hemoglobin or glycated hemoglobin (GHb), is a form of hemoglobin used to reflect the average plasma glucose concentration before a period of time (4-8 weeks). Because it contains the most HA1c content, it is sometimes abbreviated as A1C as its pronoun. Glycosylated hemoglobin is formed by non-enzymatic glycation. Glycosylation of hemoglobin can affect nephropathy and retinopathy in diabetic patients. Monitoring glycosylated hemoglobin is beneficial to improve the treatment of patients with type 1 diabetes. Methods for measuring glycosylated hemoglobin are currently widely used in simple column chromatography with cation exchange resins. Other methods include high-pressure liquid chromatography, colorimetry, isoelectric focusing electrophoresis, and radioimmunoassay.

Glycosylated hemoglobin

Right!

Glycosylated hemoglobin, English name Glycosylated hemoglobin or glycated hemoglobin (GHb), is a form of hemoglobin used to reflect the average plasma glucose concentration before a period of time (4-8 weeks). Because it contains the most HA1c content, it is sometimes abbreviated as A1C as its pronoun. Glycosylated hemoglobin is formed by non-enzymatic glycation. Glycosylation of hemoglobin can affect nephropathy and retinopathy in diabetic patients. Monitoring glycosylated hemoglobin is beneficial to improve the treatment of patients with type 1 diabetes. Methods for measuring glycosylated hemoglobin are currently widely used in simple column chromatography with cation exchange resins. Other methods include high-pressure liquid chromatography, colorimetry, isoelectric focusing electrophoresis, and radioimmunoassay.

Chinese name

Glycosylated hemoglobin

Foreign name

Glycosylated hemoglobin or glycated hemoglobin (GHb)

Explanation

Is a form of hemoglobin

Use

Reflect average blood glucose concentration over time

In 1958, Huisman and Meyering used a column for the first time to separate glycosylated hemoglobin from other forms of hemoglobin. Bookchin and Gallop first described the characteristics of glycoproteins in 1968. In 1969, Samuel Rahbar and colleagues first reported an increase in glycosylated hemoglobin in people with diabetes. In 1975, Bunn and his colleagues described the reactions that lead to the formation of glycosylated hemoglobin. In 1976, Koenig and his colleagues proposed using glycosylated hemoglobin to monitor the degree of control of glucose metabolism in patients with diabetes.

In a 120-day normal life span of red blood cells, glucose molecules combine with hemoglobin to form glycated hemoglobin. In those with diabetes who lack glycemic control, the amount of these glycated hemoglobins increases significantly.

Once the hemoglobin molecule is glycated, it remains unchanged. The accumulation of glycated hemoglobin in red blood cells reflects the average glucose level after red blood cells become glycated hemoglobin during the life cycle of red blood cells. The measurement of glycated hemoglobin can evaluate the therapeutic effect of monitoring long-term glycemic regulation. The level of glycated hemoglobin is proportional to the average blood glucose concentration in the first 4 weeks to 3 months. Some researchers have pointed out that this basic proportional relationship does not hold in the short term of 2 to 4 weeks.

Due to the analysis operation, the subject's age and individual biological differences may cause differences in laboratory test results. For two people with the same average blood glucose, their glycated hemoglobin levels may differ by 1%. Usually, the reference range for normal values is 4% ~ 5.9%.

Diabetic patients with persistently elevated blood glucose will have higher levels of glycated hemoglobin. Although the standards for treating diabetes vary, most include indicators of glycated hemoglobin levels. Diabetic patients with good glycemic control will have their glycated hemoglobin levels close to or within the reference range. The International Diabetes Federation and the American Endocrine Society recommend that the level of glycated hemoglobin is below 6.5%, while the American Diabetes Association recommends that most patients should be below 7.0%. High glycated hemoglobin levels indicate poor glycemic control. Sustained elevated blood glucose (and therefore hemoglobin levels) will increase the risk of long-term vascular complications of diabetes, such as coronary artery disease, heart attack, stroke, heart failure, kidney failure, insomnia, impotence, neuropathy (perception (Especially lower feet), gangrene, gastroparesis (slow gastric emptying). Poor glycemic control also increases the risk of short-term surgical complications, such as difficult wound healing.

In people with shorter red blood cell life, lower glycated hemoglobin levels than expected, such as those with glucose-6-phosphate dehydrogenase deficiency, patients with sickle cell disease, or any other condition that can cause early red blood cell death. Conversely, in people with long red blood cell life, glycated hemoglobin levels are higher than expected, such as those with vitamin B12 or folic acid deficiency.

The approximate correspondence table between the glycated hemoglobin level and the average blood glucose measurement value before 4 ~ 12 weeks is as follows:

Glycated hemoglobin mean blood glucose

(%) (Mmol / L) (mg / dL)

4 3.3 60

5 5.0 90

6 6.7 120

7 8.3 150

8 10.0 180

9 11.7 210

10 13.3 240

11 15.0 270

12 16.7 300

13 18.3 330

14 20.0 360

Glycated hemoglobin is recommended for (a) checking the blood glucose control status of patients with pre-diabetes, and (b) monitoring of blood glucose control in patients with high blood glucose, and during period of diabetes. For a single blood sample, it provides more information about blood glucose status than fasting blood glucose levels. In other words, the measurement of fasting blood glucose is crucial for making treatment decisions. The American Diabetes Association guidelines similar to other health care agencies recommend that those with diabetes who are meeting treatment goals (and have stable glycemic control) do at least twice a year to measure glycosylated hemoglobin, and those who have changed treatments or have not reached blood glucose Indicators of diabetic patients should be tested for glycosylated hemoglobin every quarter.

If the patient's diet or treatment plan changes within 6 weeks, it is not appropriate to measure the glycosylated hemoglobin. Similarly, if the test shows normal erythrocyte aging and mixed hemoglobin subtypes, recent blood loss or hemolytic anemia, or genetic mutations in hemoglobin molecules (globin disease) such as sickle cell disease and other diseases are not suitable. Determination of Cooperative Glycosylated Hemoglobin. In this case, the fructosamine test can be selected, which can also reflect the average blood glucose level 2 to 3 weeks ago.

For the glycosylated hemoglobin test, many laboratories differ, and there is a lack of uniform diagnostic boundaries. Therefore, no medical institution currently recommends this test for the diagnosis of diabetes, and the fasting blood glucose and oral glucose tolerance tests are currently used.