Hemoglobin A1c (HbA1c) is the standard measure used for monitoring and diagnosis of diabetes. However, HbA1c has certain limitations. Measurement of HbA1c requires a whole blood sample, HbA1c is influenced by altered red cell turnover (e.g., asplenia, iron deficiency, and anemias), and some hemoglobin variants can interfere with some HbA1c assays (www.ngsp.org). Glycated albumin is an alternative laboratory test of hyperglycemia that can be measured in serum or plasma and is independent of hemoglobin and red cell turnover. There is growing interest in whether glycated albumin testing can play a useful role in diabetes care alongside HbA1c.
There are limited data linking glycated albumin to clinical outcomes and few studies have examined the ability of glycated albumin to identify undiagnosed diabetes compared to standard tests (HbA1c and fasting plasma glucose).
In three studies using data from a nationally representative sample of the US adult population of >10,000 people, we examined the association of glycated albumin with chronic kidney disease (1), evaluated if glycated albumin was associated with cardiovascular and all-cause mortality (2), and assessed if glycated albumin could identify people with undiagnosed diabetes (3).
In the first study, we found similar association for glycated albumin and HbA1c with kidney disease (1), with stronger associations among adults with diabetes. In the second study, we found that higher levels of glycated albumin were associated with all-cause and cardiovascular mortality, with similar associations to HbA1c (2). Finally, in the third study, we found that glycated albumin showed excellent performance to identify individuals with undiagnosed diabetes in the general US adult population (3). High glycated albumin values had nearly perfect specificity, meaning that in people with high glycated albumin, virtually all had diabetes. However, the sensitivity of glycated albumin was low to moderate, meaning that glycated albumin did not perform well to identify more mild levels of hyperglycemia.
In summary, our studies in a national sample of the US adult population demonstrate that glycated albumin may be a useful alternative test of hyperglycemia in some patients when HbA1c is not available. Glycated albumin had similar prognostic information to HbA1c for kidney disease and mortality and had excellent ability to identify people with overt hyperglycemia. Nonetheless, glycated albumin has its own limitations. Glycated albumin is affected by albumin metabolism and may be inaccurate in liver cirrhosis, hypothyroidism, thyroid dysfunction and among persons with chronic inflammation (e.g., smokers) or obesity. The current evidence suggests that glycated albumin may have a limited role in some settings where HbA1c testing is problematic or unavailable.
- Kim H, Tang O, Rebholz CM, Grams ME, Coresh J, Christenson RH, et al. Associations of glycated albumin and HbA1c with chronic kidney disease in US adults. J Appl Lab Med. 2022;jfac006.
- Rooney MR, Daya N, Tang O, McEvoy JW, Coresh J, Christenson RH, et al. Glycated albumin and risk of mortality in the US adult population. Clin Chem. 2022;68:422–30.
- Fang M, Daya N, Coresh J, Christenson RH, Selvin E. Glycated albumin for the diagnosis of diabetes in US adults. Clin Chem. 2022;68:413–21.