Download The Glycomark Test

The GlycoMark Test
The GlycoMark® test is a measurement of the two-week average of blood glucose,
which can be used in addition to regular fasting blood glucose and A1c testing. The test
aides physicians in seeing the stability of blood glucose, even if the A1c remains
unchanged, and gives medical practitioners the ability to quickly gauge how well a
change in a patient’s insulin or medication regimen is working. After all, the blood
glucose may have dramatic highs and lows, but the A1c test might give a false
impression that everything is well, because the average of the highs and lows is within
normal range.
The test measures 1,5-anhydrogluticol (1,5-AG), which is a sugar naturally occurring in
many of the foods that we eat with the highest concentration found in bread, pasta,
rice, beef, pork, tea, and soy. High levels of 1,5-AG are good. In individuals who do not
have diabetes, or in individuals with well-controlled diabetes, 1,5-AG is stored at a
steady state in the tissues and blood and levels stay high. However, in people with
diabetes, 1,5-AG does not stay in the body as it should when blood glucose averages
more than 180 milligrams per deciliter (mg/dL). 1,5-AG is filtered through the kidneys
and most of it is reabsorbed back into the blood in the renal proximal tubules. When too
much glucose is present in the kidneys, the excess is reabsorbed first in the renal
proximal tubules, so an excess of glucose impedes 1,5-AG from being reabsorbed and it
is lost in the urine. If the GlycoMark test result is < 10 microgram per milliliter (μg/mL), it
is indicative of frequent hyperglycemia of > 180 mg/dL, which is the renal threshold,
over the past two weeks. The lower the GlycoMark results, the higher the average daily
peak glucose.
GlycoMark result (1,5- AG
(μg/mL)
<2
3
4
5
6
7
8
9
10
11
12
14
>14
Approximate daily average
blood glucose (mg/dL)
>290
248
225
212
203
196
191
186
184
182
180
<180
How often blood glucose is
spiking > 200 mg/dL
Daily or very frequently
Frequently
Occasionally
Rarely
When compared to continuous glucose monitoring among individuals with type 1 and
type 2 diabetes who have A1cs of < 8%, the GlycoMark test correlated significantly to:
 Mean postprandial maximum glucose (MPMG)
 Mean blood glucose (MBG)
 Standard deviation (SD)
 Mean amplitude glycemic excursion (MAGE)
 Mean of the daily difference (MODD)
 Area under the curve over 180 mg/dL (AUC-180)
Researchers evaluated the value and significance of 1,5-AG among people with type 2
diabetes living in China, and used the data to clarify the relationship between 1,5-AG
and traditional indexes of glycemic excursions via continuous glucose monitoring in 576
healthy individuals and 292 patients with diabetes. Serum levels of 1,5-AG among the
healthy individuals were 28.44 + 8.76 μg/mL with significant gender bias. Among the
individuals with type 2 diabetes, 1,5-AG was 4.57 + 3.71. The researchers found a
correlation between 1,5-AG and glycated hemoglobin, fasting blood glucose, and
postprandial blood glucose; a negative correlation was found between 1,5-AG and mean
blood glucose, standard deviation of blood glucose, and the mean amplitude of glucose
excursions.
Among 71 outpatients with type 2 diabetes who were randomly recruited from the
Chinese People’s Liberation Army, 1,5-AG was much better than either the A1c or the
serum glycated albumin as a marker of glycemic excursions. It was the best metric for
determining postprandial glucose among patients with moderately or well-controlled
diabetes. A1c and serum glycemic albumin were superior for monitoring mean blood
glucose and fasting blood glucose.
Individuals with type 1 and type 2 diabetes with an A1c between 6.5% and 6.8% wore
continuous glucose monitors for two consecutive 72-hour periods. Maximum glucose,
maximum postprandial glucose, and the area under the curve for glucose > 180 were
compared 1,5-AG, fructosamine, and A1c at the baseline, day four, and day seven.
Results showed that 1,5-AG reflected glycemic excursions, often in the postprandial
state, more solidly than either A1c or fructosamine.
A total of 55 patients were examined to compare self-reported postprandial blood
glucose levels for correlation with 1,5-AG values over a three-day period, a one-week
period, and then weekly for up to 12 weeks. The rate of correlation was lower with
fasting and preprandial blood glucose and best reflected the two-hour postprandial
glucose levels of the two previous weeks.
Researchers tested 1,5-AG levels at acute phase after acute myocardial infarction onset
are related to severity of left ventricular dysfunction. Low plasma 1,5-AG levels were
closely associated with extent of severely injured myocardium, systolic and diastolic
function at one month in patients with acute myocardial infarction, suggesting that
postprandial hyperglycemia before acute coronary events may become a new predictor
of left ventricular dysfunction after acute myocardial infarction.
The GlycoMark test cannot be used to detect hypoglycemia and it is not specifically
Food and Drug Administration- (FDA) cleared for use in pediatric patients, and pediatric
reference ranges have not been established. Secondary to varying and lower renal
thresholds, the test may have lower values during pregnancy.
References and recommended readings
GlycoMark website. http://www.GlycoMark.com. Accessed November 11, 2015.
Contributed by Elaine Hinzey, RDN, LD/N
Review date: 11/3/15