A relatively new laboratory test that indicates whether someone has had high blood glucose levels over the previous one to two weeks. The GlycoMark test can be especially useful for determining whether a person experiences blood glucose “spikes” after meals.
There is very strong scientific evidence that keeping blood glucose levels close to the normal range can help reduce the risk of diabetic complications, such as diabetic eye disease, kidney disease, and nerve damage. There is also some evidence that tight blood glucose control can lower the risk of heart disease, the leading cause of death in people with diabetes.
Currently, the most commonly used laboratory test for evaluating blood glucose control is the HbA1c test. A person’s HbA1c test result is a measure of his overall blood glucose control over the preceding two to three months.
Over the past decade, diabetes researchers have begun to focus on the importance of blood glucose levels following meals. A growing body of evidence suggests that high blood glucose levels after meals put people with diabetes at increased risk for developing macrovascular (large-blood-vessel) complications such as atherosclerosis, heart disease, and stroke, and that controlling blood glucose levels after meals can substantially lower this risk.
GlycoMark was approved for marketing in the United States by the US Food and Drug Administration in 2003. The test measures the level of a type of sugar called 1,5-anhydroglucitol (1,5-AG) in the blood. Like glucose, 1,5-AG is absorbed by the kidneys, with some of both excreted in the urine. The two are chemically very similar — so similar, in fact, that 1,5-AG “competes” with glucose for reabsorption back into the bloodstream from the kidneys. The result is that when someone’s blood glucose level rises above about 180 mg/dl, 1,5-AG begins to be excreted in the urine at a greater level, and the level in the blood goes down; it takes one to two weeks to return to normal.
Because a decreased 1,5-AG level is the result of blood glucose levels above 180 mg/dl, it usually indicates that a person has had big “spikes” in blood glucose following meals. In a 2006 study published in Diabetes Care, researchers found that GlycoMark can detect high blood glucose after meals even when these levels do not contribute to a significantly higher HbA1c level. This makes GlycoMark an especially useful new tool for evaluating overall blood glucose control.
To read more about the HbA1c test, visit www.diabetesselfmanagement.com/2/HbA1c.