Sure, you test your glucose level several times a day. You're aware of diet and exercise issues and do your best to stay on track. But what about your hemoglobin A1c level? What does it mean and why is it so important? When is the last time you had it checked? How often should you have it checked?
The hemoglobin A1c test is a simple lab test that shows the average amount of sugar in your blood over the last two to three months. It's the best way to find out if your blood sugar is under control. All people with type 2 diabetes should have a hemoglobin A1c test at least twice a year. If your treatment changes or if your blood sugar level stays too high, you should get a hemoglobin A1c test at least every three months until your blood sugar level improves. Regular testing will help you and your doctor to track your blood sugar levels over time and plan long-term treatment options to reach your target level of control.
Hemoglobin is an oxygen-carrying pigment-it's what makes red blood cells red. The hemoglobin A1c test, sometimes called a glycated hemoglobin test, measures the proportion of hemoglobin molecules in your red blood cells that have glucose attached to them (and thus are "glycated"). Once glycated, a hemoglobin molecule stays that way throughout the 3- to 4-month lifecycle of its red blood cell. Red blood cells are continually dying and being replaced, so at any given time they have a range of ages in your body. In a sense, your blood tells the history of your glucose level over the last few months. For example, if your levels were not in control three weeks ago, glycated hemoglobin will persist in the blood cells that were active at that time. If your blood sugar tends to go up at night, when you are less likely to self-monitor, your HbA1c test will indicate a higher average level of blood sugar than you found through self-monitoring.
The hemoglobin A1c goal for people with type 2 diabetes is less than 7%. The findings of a major diabetes study, the Diabetes Control and Complications Trial (DCCT), showed that people who keep their hemoglobin A1c levels close to 7% have a much better chance of delaying or preventing complications that affect the eyes, kidneys, and nerves than people with hemoglobin A1c of approximately 9%. The United Kingdom Prospective Diabetes Study (UKPDS), a 20-year study that involved more than 5000 people with type 2 diabetes, showed that intensive blood glucose control significantly reduces the risk of major diabetic eye disease and early kidney damage. The study concluded that complications from diabetes should not be seen as a natural and expected outcome-good management of blood glucose and blood pressure can prevent or delay complications for many people.
You can do a lot to bring down a high blood sugar level and get it under control. Start by asking your healthcare provider for a hemoglobin A1c test. If your hemoglobin A1c test result is too high, talk to your healthcare provider about how to lower it. (A change in treatment is almost always needed if your hemoglobin A1c is over 8%.) Keep the 7% goal in sight, but remember that lowering your hemoglobin A1c levels by any amount improves your chances of staying healthy. To get your blood sugar under control, follow a daily diet plan, stick to a physical activity program, take your prescribed type 2 diabetes medicines, and consult your healthcare provider often.
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For More Information
- Rick Mendosa: "Standardizing the A1c"
- National Diabetes Education Program HbA1c Quiz
- American Diabetes Association
- NIDDK: Health Information: Diabetes