Hemoglobin A1c or HbA1c is a protein on the surface of red blood cells. The HbA1c test is used to monitor blood sugar levels in people with type 1 and type 2 diabetes over time. Normal HbA1c levels are 6% or less. HbA1c levels can be affected by insulin use, fasting, glucose intake (oral or IV), or a combination of these and other factors. High hemoglobin A1c levels in the blood increases the risk of microvascular complications, for example, diabetic neuropathy, eye, and kidney disease.
In this health topic, we explain the dangers of hyperglycemia, or high blood sugar levels, and diabetes. Hyperglycemia causes many of the warning signs of diabetes listed above. Hyperglycemia may be caused by skipping or forgetting your insulin or diabetes medicine, eating too many grams of carbs for the amount of insulin administered, simply eating too many grams of carbs in general, or from stress or infections.