Diabetes Mellitus (DM) is a very common chronical disease of our country. In diagnosis of DM and monitoring of glycemic values, besides glucose,HbA1c is also being used. However HbA1c cannot reflect glycemic levels for short term and also, conditions like anemia, hemoglobinopathies and chronic kidney disease restrict its use. 1,5-anhidroglusitol (1,5-AG) is a monosaccharide which structurally resembles glucose. It is mainly taken into the body with foods and cannot be metabolized. It is excreted from the kidneys. 99.9% of it is reabsorbed. When renal threshold for serum glucose is exceeded, the reabsorption of 1,5-AG is inhibited and serum levels decrease. Owing to this property, serum 1,5-AG levels indirectly reflecthyperglicemia periods in the body. Having reflecting short term glucose elevations and not being affected from situations which affect HbA1c results, 1,5-AG can be helpful in diagnosis and monitoring of diabetes.