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Glycated albumin (GA) is an intermediate marker for glycemic control, reflecting blood glucose levels over the past two to three weeks. Asahi Kasei Pharma Corporation developed Lucica™ Glycated Albumin assay kit. This liquid reagent uses a unique enzymatic method to measure glycated albumin and has received 510(k) clearance from the US FDA.
Glycated albumin (GA) is a product from the glycation of serum albumin and is defined as albumin containing lysine residues bound to glucose (glycated lysine).
Fig. 1 The structure of human serm albumin
Albumin is the most abundant protein in human blood.
Human serum albumin contains 59 lysine residues. Four lysine residues ( red in Fig.1)
are mainly glycated in albumin.1
1）Iberg N and Flückiger R, J Biol Chem. 1986;261(29):13542-5.
GA reflects the glycemic status in the preceding two to three weeks because the half-life of glycated albumin (GA) is about 17 days2.
Fig. 2 Relationship between glycated proteins and past plasma glucose levels (based on Reference 2)
2）Tahara Y and Shima K, Diabetes Care. 1995;18(4):440-7.
In 30 patients receiving glucose-lowering therapy (prospective multicenter study in the United States), changes in GA at four weeks were concordant with changes in A1C at twelve weeks.3
3) Desouza CV, et al., Endocr Pract. 2015 Nov;21(11):1195-203.
In the 24-week prospective study, changes in GA between study visits were concordant (increased or decreased in the same direction) with MBG changes 60.8% of the time, with fructosamine changes 55.5% of the time, and with A1C 45.5% of the time.4
Design: 24-week prospective study of assay performance. Eight US clinics.
Subjects: Type 1 (n = 73) and type 2 diabetes (n = 77) undergoing changes to improve glycemic control (n = 98) or with stable diabetes therapy (n = 52).
Interventions: GA, fructosamine, and A1C measured at prespecified intervals. Mean blood glucose (MBG) calculated using weekly self-monitored blood glucose profiles.
4) Desouza CV, et al., J Clin Endocrinol Metab. 2020 Mar 1;105(3).
Desouza CV, et al., Results of a Study Comparing Glycated Albumin to Other Glycemic Indices. https://doi.org/10.1210/clinem/dgz087
©2019 Desouza CV, et al. ; licensee Oxford University Press
Creative Commons Attribution License (http://creativecommons.org/licenses/by/4.0/)
Fructosamine is a generic term that refers to all glycated serum proteins, including glycated albumin, in blood serum. Lucica™ Glycated Albumin assay kit selectively measures glycated albumin. The fructosamine assay measures the total concentration of glycated serum proteins, which can fluctuate because of acute systemic illness or liver disease. However, glycated albumin assays, such as Lucica™ Glycated Albumin assay kit, measure the ratio of glycated albumin to total albumin, which minimizes interference from concentrations of glycated and non-glycated albumin.
Because the GA is produced through the glycation of human serum albumin, it is not affected by pathologies with the erythrocyte lifespan altered, such as renal anemia, under treatment with dialysis or erythropoietin, iron-deficiency anemia, or the recovery phase of iron deficiency anemia.
On the other hand, attention is necessary in pathologies with the albumin metabolism altered.
| ✔ | Pathologies presenting higher GA levels with respect to blood glucose levels Diseases with albumin metabolism delayed: Hypothyroidism,5 hepatic cirrhosis,6 and emaciation7 |
| ✔ | Pathologies presenting lower GA levels with respect to blood glucose levels Diseases with albumin metabolism enhanced: Hyperthyroidism,5 treatment with glucocorticoids,8 Cushing’s syndrome,9 nephrosis,10 and advanced obesity11 |
5) Koga M, et al., Diabetes Res Clin Pract. 2009 May;84(2):163-7.
6) Miyamoto H, et al., Rinsho Byori. 2008 Sep;56(9):761-6. Japanese.
7) Koga M, et al., Clin Chim Acta. 2007 Mar;378(1-2):48-52.
8) Iizuka K, et al., BMJ Case Rep. 2016 Mar 9;2016 pii: bcr2016214788
9) Kitamura T, et al., Clin Chim Acta. 2013 Sep 23;424:164-7.
10) Okada T, et al., Intern Med. 2011;50(1):23-9.
11) Koga M, et al., Clin Chim Acta. 2015 Jan 1;438:19-23.
“Best Practice for Diabetic Patients on Hemodialysis 2012” issued by the Japanese Society for Dialysis Therapy includes the following description in the Targets for Glycemic Control Statements.
| ✔ | Pre-dialysis casual plasma glucose and glycated albumin (GA) levels are recommended as indicators for glycemic control. |
| ✔ | The hemoglobin A1c (HbA1c) level might be used only as a reference, because the HbA1c level decreases in the presence of anemia or erythropoiesis-stimulating agents (ESAs) and may not accurately represent glycemic control in hemodialysis patients. |
| ✔ | Pre-dialysis casual plasma glucose levels (or 2-h postprandial plasma glucose levels) <180–200 mg/dL |
| ✔ | For hemodialysis patients, GA levels <20.0% are recommended |
| ✔ | For hemodialysis patients with a history of cardiovascular events and who have hypoglycemic episodes, GA levels <24.0% are suggested. ＊Further studies are required to definitively determine target values. |
Nakao T. et al., Best practice for diabetic patients on hemodialysis 2012.Ther Apher Dial. 2015 Mar;19 Suppl 1:40-66.
GA is less susceptible to the effect of maternal iron metabolism and therefore useful in strict glycemic control during pregnancy.
Hiramatsu Y et al., Endocr J. 2012(59):145-151
The following reports are available:
１) Sugawara D. et al., “Glycated albumin level during late pregnancy as a predictive factor for neonatal outcomes of women with diabetes.” J Matern Fetal Neonatal Med 2018 (15):2007-2012
２) Li HP. et al., “Association between glycemic control and birthweight with glycated albumin in Chinese women with gestational diabetes mellitus.” J Diabetes Investig 2016 Jan;7(1):48-55.
