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GlycoMark (1,5-Anhydroglucitol)

GlycoMark (1,5-Anhydroglucitol)

Test Summary

GlycoMark® (1,5-Anhydroglucitol)

  

Clinical Use

  • Intermediate-term monitoring of glycemic control in patients with moderate- to well-controlled diabetes

Clinical Background

Tight glycemic control is essential for preventing the complications of diabetes. The clinical standard for evaluating glycemic control is the measurement of hemoglobin A1c (HbA1c); elevated levels (>7.0%) indicate significant hyperglycemia. However, even in patients with well-controlled HbA1c levels, postprandial glucose levels may be significantly elevated and lowering these will further improve control.

1,5-Anhydroglucitol (1,5-AG) is a glucose-like monosaccharide contained in food. Intake is normally balanced with urinary excretion; however, during periods of hyperglycemia, glucose blocks reabsorption of 1,5-AG in the renal tubules. Thus, low blood levels of 1,5-AG are associated with hyperglycemia. 1,5-AG levels change more rapidly than HbA1c levels and reflect glycemia over the previous 1-2 week period.

Individuals Suitable for Testing

  • Patients with type 1 or 2 diabetes mellitus

Method

  • Enzymatic release of hydrogen peroxide followed by colorimetric detection

  • Analytical sensitivity: 0.2 µg/mL

  • Reportable range: 0.2-110 µg/mL

Interpretive Information

In patients with moderate- to well-controlled diabetes (HbA1c <8.0%), increasing 1.5-AG levels reflect a positive short- to intermediate-term response to changes in diet or medication. In patients with poorly-controlled diabetes, in vivo levels of 1,5-AG may be depleted; thus, in this group 1,5-AG measurements may not accurately reflect therapeutic response. Increased levels are also associated with intravenous hyperalimentation and some Chinese medicines (eg, polygala tenuifolia and senega syrup).

Low levels (<8 μg/mL) of 1,5-AG primarily reflect postprandial hyperglycemia (ie, glucose >180 mg/dL). They are also associated with pregnancy, kidney disease, advanced cirrhosis, prolonged inability to intake food orally, and with steroid therapy.

References

  1. Dungan KM, Buse JB, Largay J, et al. 1,5-Anhydroglucitol and postprandial hyperglycemia as measured by continuous glucose monitoring system in moderately controlled patients with diabetes. Diabetes Care. 2006;29:1214-1219.

  2. McGill JB, Cole TG, Nowatzke W, et al. Circulating 1,5-anhydroglucitol levels in adult patients with diabetes reflect longitudinal changes of glycemia. Diabetes Care. 2004;27:1859-1865.

  3. Nguyen TM, Rodriguez LM, Mason KJ, et al. Serum 1,5-anhydroglucitol (Glycomark) levels in children with and without type 1 diabetes mellitus. Pediatr Diabetes. 2007;8:214-219.
     

Content reviewed 12/2012

 
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