1,5-Anhydroglucitol (1,5-AG), sometimes known as GlycoMark, is a monosaccharide that shows a structural similarity to glucose. Its main source in humans is dietary ingestion, particularly meats and cereals. In addition, 10% of 1,5-AG is derived from endogenous synthesis. It is generally not metabolized, and in healthy subjects, it achieves a stable plasma concentration that reflects a steady balance between ingestion and urinary excretion.
Normal range: 10.7 " “32.0 Ž ¼g/mL in males; 6.8 " “29.3 Ž ¼g/mL in females.
Use
Used clinically to monitor short-term glycemic control in patients with diabetes (1 " “2 weeks)
Useful marker for postprandial hyperglycemia
Performs better than hemoglobin A1C for monitoring glucose profile in pregnancies complicated by type 1 diabetes
Interpretation
Increased In
1,5-AG may be increased during IV hyperalimentation.
Decreased In
Individuals with renal glucose thresholds that are markedly different from 180 mg/dL (e.g., chronic renal failure, pregnancy, and dialysis) and in those undergoing steroid therapy.
α-Glucosidase inhibitors can decrease 1,5-AG by interfering with its intestinal absorption.
Limitations
In patients with poorly controlled DM, 1,5-AG is less sensitive to modest changes in glycemic control because of continuous glycosuria.
Levels can be influenced by factors such as dairy product, races, uric acid, triglycerides, liver disease, gastrectomy state, and cystic fibrosis.