"In the normal 120-day lifespan of the red blood cell, glucose molecules react with hemoglobin, forming glycated hemoglobin. In individuals with poorly controlled diabetes, the quantities of these glycated hemoglobins are much higher than in healthy people."
http://en.wikipedia.org/wiki/Glycated_hemoglobin
The glucose must first enter the Red Blood Cell, correct?
Assume: When glucose enters any cell, the main purpose is to "enable" energy. When it binds to hemoglobin, it's not available for that purpose.
Isn't that a waste of resources?
What happens to the glucose when the RBC dies?