Hemoglobin is the molecule inside our red blood cells that carries oxygen and
takes it to our tissues and organs. When your blood glucose levels are higher
than normal, hemoglobin combines with blood glucose to make glycosylated
hemoglobin or hemoglobin A1c. The higher your glucose levels, the higher
percentage of glycosylated hemoglobin you will have.
Red blood cells have a life span of approximately 120 days and hemoglobin gets
glycated, or linked to glucose molecules, slowly during that period of time. So,
when you check your glycosylated hemoglobin percentage, you can determine how
your blood glucose levels have been over the last three or four months.
This test is recommended every three or four months and is a complement of your
self monitoring. When you check your blood glucose levels with a monitor you get
the measure of your blood glucose levels at that specific moment, while
glycosylated hemoglobin provides information of how high your blood glucose
levels have been over a period of time.
If your results are low, you have lower risk for developing chronic
complications like kidney, eye, heart or nerve problems.
Your doctor should tell you what your glycosylated hemoglobin should be. However,
the general recommendation is to keep it below 7% and preferably, below 6% to be
certain that you are achieving a good control.
Source: US Food and Drug Administration: Glucose Meters & Diabetes Management