A hemoglobin A1C test is a blood test that reflects blood sugar levels over the three months before the test. This test can be used to diagnose diabetes and prediabetes. It is also an indicator of blood glucose control if you have diabetes.
This article explains what you need to know if you have signs of prediabetes, the range of the hemoglobin A1C test that indicates prediabetes and diabetes, who should be tested, and the steps to take to keep prediabetes from progressing to diabetes.
What Is the A1C Test?
A hemoglobin A1C test is also called glycosylated hemoglobin or A1C test. The result is reported as a percentage. It is a blood test that measures the percentage of hemoglobin that is bound to glucose.
Hemoglobin is a protein in red blood cells that carries oxygen. Normally, some of your body’s hemoglobin is bound to glucose. When blood sugar rises frequently or for long periods, this can cause a higher-than-normal percentage of hemoglobin to be bound to glucose.
A person’s A1C level may be high due to prediabetes, diabetes, and poorly controlled diabetes. It is a reflection of blood glucose levels over the course of the three months before the test.
Diagnosing Prediabetes
Prediabetes is a condition that precedes the development of type 2 diabetes. It is not associated with type 1 diabetes.
With type 2 diabetes, lifestyle factors have a strong impact on disease risk, and genetics can play a role as well. Type 1 diabetes is caused by genetic and environmental risk factors.
Type 1 diabetes almost always develops during childhood or adolescence, and type 2 diabetes usually develops after age 40. However, young people can get type 2 diabetes, and adults can develop type 1 diabetes.
Prediabetes is diagnosed based on these three factors:
Blood glucose level A1C test Oral glucose tolerance test
Each of these tests measures some aspect of blood sugar levels. The numbers that correspond to prediabetes are above normal levels but not as high as the numbers that indicate diabetes.
Your healthcare provider may diagnose you with prediabetes even if only one of your tests corresponds to the levels that fall into the prediabetes category.
If your blood sugar level is high, your healthcare provider may order an A1C test.
Additionally, if you have risk factors for type 2 diabetes, you might need an A1C test, even if your blood sugar is normal. That’s because most people with prediabetes can have fluctuations in blood sugar levels, so a normal measure on a random blood test doesn’t rule out prediabetes.
Risk factors for prediabetes include:
Being overweight or having obesity A history of abnormal blood sugar tests A family history of diabetes Metabolic syndrome, a group of conditions, including being overweight, having high blood pressure, and having unhealthy cholesterol levels, that increase your risk of developing heart disease, stroke, and type 2 diabetes Insulin resistance, which means that the body no longer uses insulin the way it should A history of gestational diabetes, which is diabetes that occurs during pregnancy Sedentary lifestyle, which is not being active Polycystic ovary syndrome (PCOS), a hormonal condition affecting the ovaries
Prediabetes Symptoms and Complications
You can have some symptoms caused by prediabetes, but most people don’t have any symptoms until diabetes develops. In fact, diabetes might not cause noticeable symptoms.
Possible symptoms of diabetes and prediabetes:
Excessive thirst and frequent urination Fatigue
Complications of Diabetes
The reason it’s so important to identify prediabetes is that diabetes can cause many health complications. These complications can take a long time to develop. They include:
Diabetic neuropathy: Nerve damage that causes pain, diminished sensation, and weakness Vascular disease: Can cause blood vessels to become narrow and diseased and may lead to heart disease or stroke Diabetic retinopathy: Causes vision loss Impaired wound healing: Can cause cuts, sores, and wounds to take a long time to heal Weak immune system: Causes a tendency to have frequent or severe infections and slow recovery from infections Diabetic nephropathy: Deterioration of kidney function
Diabetes requires long-term treatment for blood sugar management.
Other Tests for Prediabetes
The tests that are used to diagnose diabetes include glucose levels, A1C, and oral glucose tolerance test. Some other tests may support the diagnosis or identify risk factors, but only those three glucose-based tests are used to establish a diagnosis of diabetes.
Next Steps
If you have been diagnosed with prediabetes, this means that you need to take measures to maintain a healthy blood sugar level. Prediabetes is considered a treatable condition, and treatment can delay or completely prevent type 2 diabetes.
Lifestyle Changes
Depending on your personal habits and risk factors, certain lifestyle adjustments can lower your risk of developing diabetes.
The features of metabolic syndrome change the body’s processes that alter metabolism in ways that can lead to diabetes. Many of the lifestyle changes that can help reverse prediabetes are focused on these factors.
Steps you might be advised to take:
Losing weight if you are overweight Lowering your cholesterol (with diet or medication) if it’s too high Avoiding foods and drinks that contain high amounts of simple sugars, such as sugar-sweetened drinks or sweetened desserts Learning to modify your diet, so you have a healthy balance and timing of carbohydrate, protein, and fat intakeGetting treatment for higher blood pressure if your blood pressure is high Exercising regularly
Monitoring Blood Sugar
If you’ve had blood tests that are in the prediabetes range, you will need to have them repeated in several months.
If you’ve been advised to make lifestyle changes to control your blood sugar, repeat tests can determine whether the lifestyle changes are enough to control your blood sugar in the following ways:
If the numbers improve, you would be advised to continue your lifestyle modifications. If the numbers don’t improve or fall into the diabetes category, you would need to start taking treatment for diabetes.
Depending on how far from normal your blood sugar or A1C levels are, you might need to periodically check your blood sugar at home. You can learn to use a simple home device to do this. You and your healthcare provider would discuss the frequency, what you need to do if your glucose is high or low, and how to track your levels over time.
Summary
Prediabetes is a condition that’s diagnosed based on changes in blood glucose tests, including the hemoglobin A1C test. The A1C test is often performed as part of a yearly health checkup, or may be ordered if you have risk factors for prediabetes. The range for a diagnosis of prediabetes is an A1C of 5.7% to 6.4%.
In general, prediabetes precedes the development of type 2 diabetes. Lifestyle adjustments include weight management, getting adequate physical exercise, and following a diet plan that moderates the type and timing of sugar and carbohydrates. These are among the most important aspects of managing prediabetes.
A Word From Verywell
While prediabetes is serious and you shouldn’t ignore it, the condition can be managed and sometimes even reversed. An A1C test is a common test that’s used to identify prediabetes. You might need this test if you have risk factors for diabetes or if you’ve had a high blood sugar on a fasting or nonfasting blood test.
Your A1C will reflect optimal blood sugar control, but if your blood glucose has not been well controlled in the past, it will take weeks or months for you to see a change in your A1C numbers.
Complex carbohydrates are generally recommended instead. These include foods like whole grains. Other carbohydrates that are often recommended include fruits and vegetables.
A balance of protein, carbohydrates, and fat is considered optimal for people who have diabetes or prediabetes. It is often a good idea to consult with a nutritionist or dietitian for advice about how to manage a diet with diabetes or prediabetes.
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