If recent bloodwork results revealed high A1C levels, you may feel worried about your health—and confused. While fasting blood sugar and HbA1c (a.k.a A1C) tests both measure blood sugar, they provide different information about your body’s glucose levels. It is entirely possible to have a normal fasting blood sugar but a high A1C if your blood sugar spikes significantly at other times, such as after meals, and then returns to normal by the time you are tested in a fasted state.” Was your high A1C caused by a sneaky factor? “When red blood cells live longer than usual, such as in iron deficiency anemia, they have more time to accumulate sugar, which can make the A1C look higher than your true average blood sugar.”