he glycohemoglobin test was developed in the late 1970's.
Other names that have been used to describe the same test are glycosylated hemoglobin, and hemoglobin A1c.
This test gives information about your average blood sugar level during the past two or three months. The normal values for this test vary depending upon the
lab,
and you must look at the "normal range" or "reference range" that the lab uses to make sense of your result(1). If your glycohemoglobin value is higher than the normal range, then we know that your average blood sugar has been elevated during the past two months. More importantly,
if your recent glycohemoglobin is lower than your previous value,
then we know that you are now doing better than before!
Fructosamine
The fructosamine test
has been developed more recently.
Fructosamine
is a term referring to the linking of blood sugar
onto protein molecules in the bloodstream.
Fructosamine levels have been shown to change more rapidly than glycohemoglobin.
Your fructosamine value depends upon your average blood sugar level during the past three weeks.
Therefore, it might be able to detect changes
in diabetic control earlier than the glycohemoglobin.
The fructosamine test could be viewed as complementary
to the glycohemoglobin,
since the two tests are different reflections of diabetes control:
glycohemoglobin looks back approximately eight weeks,
and the fructosamine test looks back about three weeks.
Other tests
Other tests similar to the fructosamine test have been proposed;
the glycosylated protein test
is an example of another test that was suggested.
Unfortunately, these newer tests are less reliable than originally hoped, and seems unlikely that
either the fructosamine test or the glycosylated protein test
will ever become as widely used for monitoring diabetes as the glycohemoglobin level.
What to do
Therefore, to evaluate your diabetes control,
you should arrange to get a glycohemoglobin level measured
approximately every three months.
By using this test, together with your
home blood sugar monitoring, you and your health care team
will have a much better idea about how your diabetes is doing.
Footnotes:
(1) There are efforts underway to standardize the "normal range" for the glycohemoglobin test.
See
The National Glycohemoglobin Standardization Program
Also see
HbA1c - the 7% Solution
by David Mendosa.
The Relationship Between Glycohemoglobin (GHB)/Hemoglobin A1c (HbA1c) and Plasma Glucose
From
The National Glycohemoglobin Standardization Program
The Diabetes A1C Initiative.
Effects of Hemoglobin Variants and Chemically Modified Derivatives on Assays for Glycohemoglobin. Review article
(Clinical Chemistry. 2001;47:153-163).
Check Your Hemoglobin A1c I.Q.
from the NDEP
