Diabetes and hemoglobin a1c: what is the relation?

Diabetic measure. The HgbA1C is a measure reflective of your degree of diabetic control in the long term. It essentially represents a three month average of your fingersticks, as if you took a fingerstick every minute, night and day, eating and fasting, for three months straight and then averaged them all. Technically, it's the percentage of red blood cells that have glucose attached to them.
Control. A1c is the estimation of diabetes control. It tells you the average blood sugar over the last 2-3 months. It's reported in a percentage form which correlates to an average bs value. For example, most patient's A1c goal is 7% which corresponds to an average bs of 154. 6% is average of 126.