A growing body of epidemiological and experimental evidence indicates that controlling glucose hyperglycemia and glycemic variability plays a significant role in achieving
optimal glycemic control and reducing both the microvascular and macrovascular complications of diabetes. GlycoMark® (1,5-anhydro-D-glucitol), an assay for the measurement of serum 1,5-anhydroglucitol (1,5-AG), provides a specific measure of hyperglycemia over the previous two weeks with a single, non-fasting blood test. This new test reveals potentially abnormal glucose elevations that would otherwise go undetected by the Hemoglobin A1c (HbA1c) test alone.
The presence of 1,5-AG in the human body was confirmed in 1973, and in 1977, a decrease in plasma 1,5-AG was associated with uremia and diabetes mellitus. For the past 18 years in Japan, an assay for serum levels of 1,5AG as a short-term marker for hyperglycemia has been utilized as the standard of care for diabetes, and there has been much active research on the relationship between diabetes and 1,5-AG.
1,5-AG is valuable at all levels of hyperglycemia as a short-term marker unaffected by hemoglobinopathies; however, its greatest utility is in the moderately controlled and at
goal type 1 and type 2 diabetes patient. Tests such as HbA1c and fructosamine reflect average or mean glucose over two to three months and two to three weeks, respectively.
These averages can hide significant differences in patients. In two patients with the exact same HbA1c result, one patient can be in reasonable glycemic control while another can be wildly out of control.
A study published in the American Diabetes Association Diabetes Care journal (Dungan et al. Diabetes Care 2006; 29 (6): 1214-1219) demonstrated that the GlycoMark® 1,5-AG test reflected hyperglycemia more robustly than the A1c test. The study also showed that GlycoMark® was able to reveal dramatic differences in glycemia in patients with similar A1c levels. Clinical data supports this finding as patients with identical HbA1c values below 8% can have different serum 1,5-anhydroglucitol levels. Comparative GlycoMark® and HbA1c data demonstrate that even some patients who have achieved HbA1c goal (<7.0% per ADA) are actually not in hyperglycemic control. Bonora et al (Diabetologia 2006) have shown that approximately, 40% of patients with HbA1c between 6.5% and 8% do not have adequate glycemic control. These patients will have difficulty achieving goal without intervention. GlycoMark® provides a means to differentiate these patients and to effectively monitor their treatment.
Achieving HbA1c goal is desirable. Epidemiological studies (UKPDS and DCCT) in the 1990s indicated that for each 1% decrease in HbA1c, there was a significant reduction in the risk of both microvascular (retinopathy, neuropathy and nephropathy) and macrovascular disease. A current review of patients in these studies reports a legacy effect in that those patients intensely treated for even the short duration of the study now have a lower incidence of heart failure than those that were not intensely treated. Basic research on coronary artery thickening in patients with high two-hour OGT tests support the epidemiological studies (Mellen, PB et al Arterioscler Thromb Biol 2006: 26:189-
193.) However, to date, poorly designed outcome studies have been inconclusive with respect to hyperglycemia and cardiac disease.
GlycoMark® has been FDA-approved as a non-fasting blood test for intermediate term glycemic control in diabetic patients. It is a monitoring assay for glycemia over the renal
threshold during the previous two weeks. GlycoMark® is reimbursed by Medicare and most insurance carriers. Currently, there is no testing limitation; however, a minimum of monthly is recommended. The CPT code is 84378.
GlycoMark® is very effective in monitoring drug efficacy. Pharmaceutical companies, such as Amylin, Lilly and Merck, have used GlycoMark® in studies of their antihyperglycemic
drugs. For example, in an exenatide (Byetta) study (2007 American Diabetes Association annual meeting), Amylin noted that GlycoMark® changed significantly in patients treated with 5 μg of the drug over a six month period; whereas HbA1c showed no movement over the same time.
GlycoMark® values should be obtained for HbA1c </= 8% to obtain a baseline value. For GlycoMark® levels less than 10 μg/ml modify diet and exercise and, perhaps, add an
antihyperglycemic drug. Retest monthly until the GlycoMark® levels exceed 10 μg/ml. In summary, the goal is diabetes is an HbA1c <7.0% (ADA) or <6.5 (AACE) and a GlycoMark® over 10 μg/ml.
The assay is currently performed on a general chemistry analyzer in both the reference lab and the physician office lab for those physicians that have their own on-site laboratory with a general chemistry analyzer.
For more information on GlycoMark®, please visit www.glycomark.com.
A growing body of epidemiological and experimental evidence indicates that controlling glucose hyperglycemia and glycemic variability plays a significant role in achieving optimal glycemic control and reducing both the microvascular and macrovascular complications of diabetes. GlycoMark® (1,5-anhydro-D-glucitol), an assay for the measurement of serum 1,5-anhydroglucitol (1,5-AG), provides a specific measure of hyperglycemia over the previous two weeks with a single, non-fasting blood test. This new test reveals potentially abnormal glucose elevations that would otherwise go undetected by the Hemoglobin A1c (HbA1c) test alone.
The presence of 1,5-AG in the human body was confirmed in 1973, and in 1977, a decrease in plasma 1,5-AG was associated with uremia and diabetes mellitus. For the past 18 years in Japan, an assay for serum levels of 1,5AG as a short-term marker for hyperglycemia has been utilized as the standard of care for diabetes, and there has been much active research on the relationship between diabetes and 1,5-AG.
1,5-AG is valuable at all levels of hyperglycemia as a short-term marker unaffected by hemoglobinopathies; however, its greatest utility is in the moderately controlled and at goal type 1 and type 2 diabetes patient. Tests such as HbA1c and fructosamine reflect average or mean glucose over two to three months and two to three weeks, respectively.
These averages can hide significant differences in patients. In two patients with the exact same HbA1c result, one patient can be in reasonable glycemic control while another can be wildly out of control.
A study published in the American Diabetes Association Diabetes Care journal (Dungan et al. Diabetes Care 2006; 29 (6): 1214-1219) demonstrated that the GlycoMark® 1,5-AG test reflected hyperglycemia more robustly than the A1c test. The study also showed that GlycoMark® was able to reveal dramatic differences in glycemia in patients with similar A1c levels. Clinical data supports this finding as patients with identical HbA1c values below 8% can have different serum 1,5-anhydroglucitol levels. Comparative GlycoMark® and HbA1c data demonstrate that even some patients who have achieved HbA1c goal (<7.0% per ADA) are actually not in hyperglycemic control. Bonora et al (Diabetologia 2006) have shown that approximately, 40% of patients with HbA1c between 6.5% and 8% do not have adequate glycemic control. These patients will have difficulty achieving goal without intervention. GlycoMark® provides a means to differentiate these patients and to effectively monitor their treatment.
Achieving HbA1c goal is desirable. Epidemiological studies (UKPDS and DCCT) in the 1990s indicated that for each 1% decrease in HbA1c, there was a significant reduction in the risk of both microvascular (retinopathy, neuropathy and nephropathy) and macrovascular disease. A current review of patients in these studies reports a legacy effect in that those patients intensely treated for even the short duration of the study now have a lower incidence of heart failure than those that were not intensely treated. Basic research on coronary artery thickening in patients with high two-hour OGT tests support the epidemiological studies (Mellen, PB et al Arterioscler Thromb Biol 2006: 26:189-193.) However, to date, poorly designed outcome studies have been inconclusive with respect to hyperglycemia and cardiac disease.
GlycoMark® has been FDA-approved as a non-fasting blood test for intermediate term glycemic control in diabetic patients. It is a monitoring assay for glycemia over the renal threshold during the previous two weeks. GlycoMark® is reimbursed by Medicare and most insurance carriers. Currently, there is no testing limitation; however, a minimum of monthly is recommended. The CPT code is 84378.
GlycoMark® is very effective in monitoring drug efficacy. Pharmaceutical companies, such as Amylin, Lilly and Merck, have used GlycoMark® in studies of their antihyperglycemic drugs. For example, in an exenatide (Byetta) study (2007 American Diabetes Association annual meeting), Amylin noted that GlycoMark® changed significantly in patients treated with 5 μg of the drug over a six month period; whereas HbA1c showed no movement over the same time.
GlycoMark® values should be obtained for HbA1c </= 8% to obtain a baseline value. For GlycoMark® levels less than 10 μg/ml modify diet and exercise and, perhaps, add an antihyperglycemic drug. Retest monthly until the GlycoMark® levels exceed 10 μg/ml. In summary, the goal is diabetes is an HbA1c <7.0% (ADA) or <6.5 (AACE) and a GlycoMark® over 10 μg/ml.
The assay is currently performed on a general chemistry analyzer in both the reference lab and the physician office lab for those physicians that have their own on-site laboratory with a general chemistry analyzer.
For more information on GlycoMark®, please visit www.glycomark.com.