A1C and Blood Sugar Control
When it comes to managing type 1 diabetes, A1C numbers tend to be a major focus, especially if they are higher than they should be. A big part of the diabetes care plan is centered around getting this all-important number to goal. So, what does it really mean? Let’s review what A1C actually means and why it is an important measure of blood sugar control.
How does an A1C test measure average blood sugar over the course of 2 to 3 months? The A1C test measures the amount of a protein called hemoglobin, which is found within all red blood cells, that has linked (glycated) with blood sugar. The job of hemoglobin is to carry oxygen from the lungs to all the cells of the body. Blood sugar (or glucose) enters red blood cells and links up (or glycates) with the hemoglobin molecule. The more glucose in the blood, the more hemoglobin gets glycated. Red blood cells live for about 3 months. So, by measuring the percentage of A1C in the blood, we get an overview of average blood sugar control for the past few months. It’s like a “memory” of blood sugar over time.
While both A1C tests and regular blood sugar checks show how well diabetes is being managed, A1C provides a bigger picture of blood sugar control. When you have type 1 diabetes, a health care provider should measure A1C levels at least twice a year if blood sugar goals are being reached. When the treatment plan has changed, or goals are not being reached, A1C may be tested more often, as much as 4 times a year.
The American Diabetes Association (ADA) recommends that A1C be below 7% in most people with diabetes. Lowering A1C to below 7% may help reduce the risk of some diabetes-related problems; however, A1C goals are somewhat different for everybody.
A1C compared with average blood sugar
When A1C results come back from the lab, there may be a blood sugar reading next to it. This is another way of showing the average blood sugar using the same measurement that is used in blood sugar meters, which is milligrams per deciliter (mg/dL).
A1C and Estimated Average Blood Sugar (Glucose)
|A1C (%)||Estimated Average Glucose (mg/dL)|
Adapted from the ADA Standards of Medical Care in Diabetes—2016.
Blood sugar recommendations
In addition to A1C goals, the ADA also has recommendations for what blood sugar numbers should be when they are checked throughout the day.
|A1C||Less than 7.0%|
Before a meal
After a meal
|Less than 180 mg/dL|
Remember that blood sugar goals can be different from person to person. For example, if one can achieve an A1C of less than 6.5% without risking low blood sugar (hypoglycemia), their health care provider might recommend trying to do so. However, for people with a history of dangerously low blood sugar, a less ambitious goal of less than 8% might be safer and more practical.