A1C Test for Diabetes: What You Need to Know
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If you have diabetes, your doctor may recommend you do daily (sometimes multiple times) finger pricks/sticks to measure your blood glucose (sugar). These tests are accurate but only at the moment, as your blood sugar can vary wildly depending on the time of day and your level of activity.
For more accurate information, doctors recommend A1C tests.
What is A1C?
The A1C test has been commercially available since the 1980s. Since then, it has quickly become an important tool in the diagnosis and management of diabetes. Other names for the A1C test are hemoglobin A1c test or HbA1c test, glycosylated hemoglobin test, glycohemoglobin test, glycated hemoglobin test, and just plainly A1C.
Simply put, the A1C test provides an average of your blood sugar levels over the past three months. It provides different, and complementary, information than what comes from a single finger prick. This blood test can screen for/diagnose diabetes — specifically type 1 and type 2 diabetes but not gestational diabetes.
If you have diabetes, it can give insight into whether your treatment is working and how well you are managing this serious condition. Strict control of blood sugar in diabetes, reflected by lower A1C values, has been shown to slow the progression of diabetic complications, such as eye disease (retinopathy), kidney disease (nephropathy), and nerve disease (neuropathy).
What are normal A1C levels?
The normal reference range for A1C levels in healthy adults is 4.8 to 5.7 percent. Most doctors interpret an A1C level of less than 5.7 percent as normal.
If your A1C is between 5.7 percent and 6.4 percent, your diagnosis is prediabetes. This is an important diagnosis, as having prediabetes puts you at risk for developing type 2 diabetes within 10 years.
The criterion for the diagnosis of diabetes is an A1C test greater than or equal to 6.5 percent. If diagnosed with diabetes, the American Diabetes Association (ADA) recommends an A1C level of less than seven percent as a reasonable therapeutic goal.
How do I get my A1C levels tested?
The A1C test is reliable and requires no special preparation. In other words, it does not require an eight-hour fast — unlike some other blood sugar tests — and can be performed at any time of day.
A doctor or other health care professional, such as a phlebotomist, will draw some blood and send it to a medical laboratory for analysis. Some doctors' offices offer point-of-care testing, which means the analysis is performed in the office and quickly available.
The A1C test measures how much sugar is attached to hemoglobin, a protein in red blood cells whose job is to carry oxygen. The lifespan of red blood cells is approximately 120 days, or three months, which is how the A1C test provides a three-month average of blood sugars. The result of the A1C test is a percentage.
The frequency of A1C testing varies. If you are a diabetic meeting your management goals, most doctors recommend twice per year testing. On the flip side, those not meeting blood sugar control goals or who have recently changed treatment should be tested four times per year.
Why is my A1C level high?
If your A1C level is high, it means that either you have been newly diagnosed with diabetes (A1C greater than 6.5 percent) or you have uncontrolled diabetes despite treatment (A1C greater than seven percent).
Regardless of the reason, if your A1C level is too high for too long, it can lead to severe health issues. Specifically, you are at increased risk of developing complications from diabetes (i.e., heart attack, stroke, retinopathy, nephropathy, neuropathy, slow wound healing, infection, and amputation). It can even lead to other potentially life-threatening conditions such as hyperosmolar hyperglycemic nonketotic syndrome (most commonly occurs in type 2 diabetics) and diabetic ketoacidosis (most commonly occurs in type 1 diabetics), both of which are characterized by extremely high blood sugar levels.
What blood sugar level is dangerous?
Your blood sugar level not only can be used to diagnose diabetes, but it can be used to gauge your response to treatment.
A fasting blood glucose test requires at least an eight-hour period of overnight fasting (i.e., no food or drink). Doctors consider a value of less than 110 mg/dL as a normal fasting glucose. A value greater than or equal to 110 mg/dL but less than 126 mg/dL is an impaired fasting glucose. Doctors consider this result as a diagnosis of prediabetes. Lastly, a value greater than or equal to 126 mg/dL suggests a diagnosis of diabetes and should be confirmed with repeat testing.
In terms of managing your diabetes, the ADA recommends a blood sugar level of 70 to 130 mg/dL before eating for a person with diabetes. In contrast, blood glucose levels should be less than 180 mg/dL within two hours of eating a meal.
Furthermore, the ADA recommends an A1C level of less than seven percent for those going through diabetes treatment. In contrast, the American Association of Clinical Endocrinologists recommends an A1C level of less than 6.5 percent.
How do I lower my A1C levels?
If you have prediabetes or even frank diabetes, you can lower your A1C level. The cornerstones of lowering your A1C are diet, exercise, and prescription medication.
As far as diet, you should attempt to restrict your calories and eat foods with low levels of saturated fats and sugars. Plus, it's a good idea to avoid highly processed foods (e.g., white rice, white bread, white flour, and lunch meats). As far as exercise, health care professionals recommend 30 minutes of activity per day most days of the week (approximately 150 minutes/week).
Following diet and exercise recommendations has the potential to lead to weight loss, which can significantly lower your blood sugars.
How long does it take to lower A1C levels?
With the A1C test, it takes about two to three months to see lower A1C results. As a result, there is really no need to have the test more often than every three months. However, if you are newly diagnosed and naïve to treatment, significant changes in your blood glucose may be seen within two weeks.
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