Albumin in human serum accounts for 66% of serum protein, while the rest is globulin. Glucose in serum and n-terminal of serum protein undergo non-enzymatic glycosylation reaction to generate glycosylated serum protein, while glycosylated albumin accounts for more than 90% of glycosylated serum protein. In addition, albumin content in serum is stable, while globulin may fluctuate due to infection and other diseases. Therefore, accurate measurement of glycosylated albumin is very important to accurately reflect the glucose control of diabetes mellitus.Glycosylated albumin is an indicator of average blood glucose levels over the past 2-3 weeks. The response period is shorter than that of the ‘gold standard’ hemoglobin a1c. Therefore, glycosylated albumin has advantages over glycosylated haemoglobin in the recognition of therapeutic effect and the adjustment of clinical dosage. In addition, in many cases of abnormal hemoglobin metabolism, the results of glycosylated hemoglobin cannot truly reflect the patient's blood sugar level, and the results of glycosylated albumin are not affected, such as diabetic nephropathy patients, anemia patients, pregnant women's blood sugar test.

Glycosylated albumin determination: in the sample, the glycosylated amino acid oxidase (dase) is first injected to remove endogenous glycosylated amino acids by converting them into gluconal, amino acid and hydrogen peroxide. In the treatment solution, a protease specific to albumin is injected to produce glycosylated amino acids from glycosylated albumin. Afterwards, the glycosylated amino acid oxidase is injected to produce gluconal, amino acid and hydrogen peroxide from the glycosylated amino acid. The hydrogen peroxide is quantitatively changed into blue-purple pigment under the action of peroxidase (POD) under the coexistence of TODB and 4AAP.The quantification of glycosylated amino acids from glycosylated albumin by measuring the absorbance of blue-purple pigments.

Albumin determination: bromocresol green colorimetry was adopted in this method. Under PH4.2, the albumin in the samples coupled with bromocresol green to form a blue-green complex, resulting in an increase in the absorbance at 630nm.