Salivary 1,5-Anhydroglucitol and its Correlation with Postprandial Hyperglycemia: Development and Validation of a Novel Assay

BACKGROUND: Saliva has the potential to be used as a noninvasive sample for testing hyperglycemia in diabetes mellitus. Serum 1,5-anhydroglucitol (1,5-AG) decreases with an increase in blood sugar >180 mg/dl. We hypothesized that salivary 1,5-AG can be used to identify blood sugar higher than 180 mg/dl using a novel biochemical method. AIM: This study aimed to develop a novel biochemical method for serum and salivary assessment of 1,5-AG and assess its correlation with postprandial blood sugar (PPBS) >180 mg/dl. METHODOLOGY: The study comprised 45 controls (healthy individuals) and 45 cases (type 2 diabetic patients with PPBS >180 mg/dl). Blood and salivary samples were collected according to the study protocol. A new method was developed for the quantification of 1,5-AG in serum and saliva using liquid chromatography–mass spectrometry. RESULTS: The value of serum (mean –22.19 μg/ml and median –22.12 μg/ml) and salivary (mean –0.124 μg/ml and median –0.088 μg/ml) 1,5-AG was higher in healthy individuals compared to corresponding serum (mean –3.89 μg/ml and median –2.52 μg/ml) and salivary (mean –0.025 μg/ml and median – 0.025 μg/ml) levels in diabetics with PPBS >180 mg/dl. In diabetics, a significant negative correlation was noticed with PPBS levels and 1,5-AG levels in serum and saliva. Salivary 1,5-AG level <0.054 μg/ml had an 86.4% sensitivity and 87.2% specificity in predicting a blood sugar value >180 mg/dl. CONCLUSION: The results of our study suggest that the short-term glycemic marker 1,5-AG can be detected in saliva and can be useful as an adjunct marker in monitoring of glycemic status in diabetic patients.