Background: Our previous study indicated that serum 1,5-anhydroglucitol (1,5-AG) levels slightly increased after a glucose load, therefore, this study was conducted to explore short-term changes in 1,5-AG levels after a steamed bread meal test (SBMT) and compare the agreement of 1,5-AG, glycated albumin (GA), and glycated hemoglobin (HbA1c) levels between fasting and postprandial states after an SBMT.

Methods: 104 participants were recruited and underwent a 100 g SBMT. Fasting, 30 min, and 120 min of 1,5-AG, GA, and HbA1c were measured. Statistical analysis comprised an intra-class correlation coefficient model, Passing-Bablok regression and Bland-Altman difference plot.

Results: Levels of 1,5-AG slightly increased from 30 to 120 min after an SBMT (P < 0.01), HbA1c and GA levels showed stability at 30 and 120 min. The Passing-Bablok regression linear equation showed postprandial 1,5-AG, GA, and HbA1c levels were well fitted (all P > 0.05), and Bland-Altman difference plot showed that 100% of data points for HbA1c30 and HbA1c120 fell within the limits of agreement; 94.2%, 96.2%, 95.2%, and 95.2% of data points for 1,5-AG30, 1,5-AG120, GA30, and GA120 fell within the limits of agreement, respectively. Therefore, in the same circumstances, HbA1c showed better stability than both GA and 1,5-AG.

Conclusion: Agreement analyses indicated that good stability of 1,5-AG, GA, and HbA1c levels after the SBMT. HbA1c had an optimal stability, which was superior to that of GA or 1,5-AG. Further studies in different 1,5-AG transport models are needed to investigate the relevant metabolic pathways.

Effects of oral glucose tolerance test and steamed bread meal test on serum 1,5-anhydroglucitol levels