What does my A1C mean?
An A1C test result is reported as a percentage. The number represents the portion of hemoglobin proteins that are glycated, or holding glucose. The higher the percentage, the higher your blood sugar levels have been over the last few months.
For diagnosing purposes, an A1C level of:
- Less than 5.7% means you don’t have diabetes.
- 5.7% to 6.4% signals prediabetes.
- 6.5% or higher usually indicates Type 2 diabetes (or Type 1 diabetes).
If you already have diabetes, an A1C result is a glimpse into how well your management plan has been working over the last three months. Management may involve oral pills, taking insulin, monitoring blood sugar levels and/or lifestyle changes, such as diet and exercise. Your A1C can help you and your provider determine if you should adjust any part of your treatment plan.
It’s important to remember that your A1C (if you have diabetes) is just an average measurement of your blood sugar over a few months. It’s not a grade or the ultimate determiner of whether you’re living a healthy life. Know that your A1C will change over your lifetime and that there are steps you can take to improve your diabetes management and A1C level, if needed.
A1C and estimated average glucose (eAG)
Some laboratories report your A1C results as a percentage in addition to the corresponding estimated average glucose (eAG).
The eAG calculation converts the A1C percentage to the same units you use with at-home glucose meters (glucometers) — milligrams per deciliter (mg/dL) or millimoles per liter (mmol/L). Just like your A1C is an average, the eAG is a single number that represents your average blood sugar level over the past three months.
For example, an A1C level of 7% equates to an eAG of 154 mg/dL (8.6 mmol/L). An A1C level of 9% equates to an eAG of 212 mg/dL (11.8 mmol/L).
What is a normal A1C?
For people without diabetes, a normal A1C is below 5.7%.
For people with diabetes, what’s “normal” and healthy for you depends on your goals and access to diabetes management medication and tools. Together, you and your healthcare provider will determine an A1C range that should be your target goal. This will likely change throughout your life.
In general, the American Diabetes Association recommends that the goal for most adults with diabetes should be an A1C of 7% or lower.
Your A1C goals may be above 7% if you have:
- Limited life expectancy.
- Severe low blood sugar (hypoglycemia) episodes or are unable to sense these episodes (hypoglycemia unawareness).
- Advanced diabetes complications, such as chronic kidney disease, nerve problems or cardiovascular disease.
On the other hand, healthcare providers typically recommend that people with Type 1 diabetes who are pregnant try to maintain an A1C of 6.5% or lower throughout their pregnancy. This is to try to lower potential health risks for the fetus and to try to prevent fetal macrosomia.
What is a dangerous level of A1C?
The higher your A1C levels, especially if they’re consistently high over several years, the more likely you’ll develop complications, such as:
- Retinopathy.
- Nephropathy.
- Neuropathy.
- Gastroparesis.
- Heart disease.
- Stroke.
Studies have shown that people with diabetes may be able to reduce the risk of diabetes complications by consistently keeping their A1C levels below 7%.
It’s important to remember that other factors can contribute to the development of diabetes complications, such as genetics and how long you’ve had diabetes.
Are A1C tests accurate?
Certain factors can affect the accuracy of A1C tests, including:
- Genetics, such as hemoglobin variants.
- Medical conditions.
- Medications and supplements.
- Errors in the collection, transport or processing of the test.
These factors can make your result falsely low or falsely high. Most of the factors are due to differences in the lifespan and health of your red blood cells.
Hemoglobin variants and A1C results
Hemoglobin variants can affect the results of some A1C tests.
The form of hemoglobin in your blood depends on the genes you inherit from your biological parents. There are many different forms. The most common form is hemoglobin A. Other, less common forms of hemoglobin are called hemoglobin variants.
A hemoglobin variant doesn’t increase your risk of developing diabetes, but it can affect A1C results. Labs have different ways to do A1C tests on blood with a hemoglobin variant.
The most common variants include:
- Hemoglobin C trait: Black people, people of West African descent and people from South and Central America, the Caribbean Islands and Europe are most likely to have this trait.
- Hemoglobin D trait: People who live in China, India, Turkey, Brazil and some parts of Europe are most likely to have this trait.
- Hemoglobin E trait: Asian Americans, especially those of Southeast Asian descent, are most likely to have this trait.
- Hemoglobin S trait: Black people and Hispanic Americans are most likely to have this trait.
A blood test can detect hemoglobin variants. Talk to your healthcare provider if you think you might have a hemoglobin variant that could affect your A1C results.
Causes of falsely low A1C results
The following conditions and situations can cause falsely low A1C results, meaning the result is lower than your actual A1C level:
- Alcohol use disorder.
- Blood transfusion.
- Chronic kidney failure.
- Erythropoietin-stimulating agents (ESAs).
- Hemorrhage (bleeding).
- Living at a high altitude.
- Iron supplementation.
- Cirrhosis of the liver.
- Pregnancy.
- Sickle cell anemia.
- Spherocytosis and hemolytic anemia.
Causes of falsely high A1C results
The following conditions and situations can cause falsely high A1C results, meaning the result is higher than your actual A1C level:
- Anemia, such as iron-deficiency anemia, infection-induced anemia or tumor-induced anemia.
- Certain medications, including immunosuppressant medications and protease inhibitors.
- Hypertriglyceridemia.
- Organ transplantation.
- Thalassemia.
- Vitamin B12 deficiency.
Can you have a high A1C and not have diabetes?
If you have an elevated A1C (above 6.5%) for the first time, it doesn’t always mean that you have diabetes. Other factors, such as certain medications (like steroids) or sickness can temporarily increase your blood sugar levels. Anemia and other conditions can cause a falsely high A1C result, as well. There also could’ve been an error in the collection, transport or processing of the test.
Healthcare providers rely on more than one test to diagnose diabetes. For example, they may order a fasting blood glucose test or another A1C test. In any case, your provider will carefully interpret your results and discuss them with you.
