The hemoglobin A1C test is the closest thing to a diabetes scorecard you can find. Whether someone has had diabetes mellitus for years or if they have just been diagnosed, they have probably heard about this test. Unlike blood sugar meters people use at home, the A1C measures an average blood sugar level over the past several months by analyzing how many of a patient’s hemoglobin cells have glucose attached to them. The test results keep track of how well a person is managing his or her diabetes.
What does A1C stand for?
Hemoglobin A1C (HbA1C), commonly called A1C, stands for glycosylated hemoglobin. An A1C test (sometimes called the HbA1C test or glycohemoglobin test) provides information on how well-controlled a person’s diabetes is. “It does this by measuring the percentage of red blood cell hemoglobin protein that has sugar stuck to it and provides a three-month average of your blood glucose levels,” explains Marie Bellantoni, MD, a board-certified endocrinologist at the Center for Endocrinology at Mercy Medical in Baltimore. The higher blood sugar levels are, the more glucose attaches to hemoglobin. The results provide patients and their healthcare providers with information on how well their treatment, diet, and medication is working and whether adjustments are necessary.
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There are a few reasons a doctor might suggest an A1C test:
- To make a diagnosis of Type 2 diabetes
- To test for prediabetes
- To monitor blood sugar levels
- To determine if treatment adjustments are needed
The A1C blood test is not for diagnosing Type 1 diabetes, gestational diabetes, or cystic fibrosis-related diabetes, according to the National Institute of Diabetes and Digestive and Kidney Diseases (NIDDK).
Do you have to fast for an A1C blood test?
Unlike the fasting plasma glucose (FPG) and the OGTT tests, there is no need to fast before having the A1C test. If A1C test results indicate a person has or might have diabetes, a healthcare provider might suggest one of these tests to confirm the results. Another test, the random plasma glucose test, which does not require fasting, can also be used. If the results are borderline or if the results of the different tests do not match, a doctor might suggest repeating the test in several weeks or months.
How accurate are A1C tests?
A1C levels rise well before the clinical onset of diabetes, making early diagnosis possible according to the 2017 Standards of Medical Care in Diabetes by the American Diabetes Association (ADA). Sometimes, however, in the early stages of diabetes, blood sugar levels are not high enough to show up as problematic. Testing environments, such as temperature in the lab, equipment used, and handling of samples, can affect the results; however, this is more common in the fasting plasma glucose and the OGTT than in the A1C. Strict quality controls and advancements in testing have made the A1C test more precise than in the past, according to the NIDDK. Doctors should be aware of laboratories that use an NGSP-certified method of testing for A1C levels. The NIDDK warns that blood samples taken at home or analyzed in a healthcare provider’s office should not be used for diagnosis.
There are some health conditions and situations that might skew the results of the test. These include:
- Kidney failure
- Liver disease
- Sickle cell anemia
- Erythropoietin treatment
- Blood loss or blood transfusions
Also, the test can be unreliable for people of African, Mediterranean, or Southeast Asian descent, people with a family member with sickle cell anemia, and those with thalassemia. For those who fall into these groups, a healthcare provider might suggest a different test or a specialized A1C.
How often is A1C tested?
To keep A1C levels in check, patients should have the test repeated regularly. “If the A1C is less than 5.7, indicating you don’t have diabetes, you should have it checked every three years,” according to Robert Williams, MD, a family doctor and geriatrician in Lakewood, Colorado, and a medical advisor for eMediHealth. “If it is between 5.7 and 6.4, indicating you are at risk of developing diabetes, you should have it rechecked every one to two years. If you have a confirmed diabetes diagnosis, and your blood sugar is well-controlled, you should have an A1C test every six months. If you already have diabetes and your medications change, or your blood sugar is not well-controlled, you should have an A1C test every three months.”
Normal A1C levels
There are some general guidelines for interpreting A1C results. However, there are also exceptions, according to the ADA. The general guidelines are:
- Under 5.7: Non-diabetic
- Between 5.7 and 6.4: Prediabetes
- Between 6.0 and 6.9: Controlled diabetes
- Between 7.0 and 8.9: Uncontrolled diabetes
- Over 9.0: Critically high
For reference, normal A1C levels for people without diabetes is 4% to 5.6%.
What is a good A1C level?
Levels between 5.7 and 6.4 are considered prediabetes. For most people with diabetes, the general A1C goal is to have a level between 6.0 and 6.9. While it might sound like the ideal A1C target is under 6.0, for those with diabetes, this level can indicate low blood sugar levels, which can be just as dangerous as high blood sugar levels. If A1C results fall between 7.0 and 8.9, a doctor might suggest lifestyle changes or medications to help lower the levels to what is considered controlled. However, for some people, these levels might be appropriate, such as:
- Those with a limited life expectancy
- People with long-standing diabetes who have trouble reaching a lower goal
- Those with severe hypoglycemia or the inability to sense hypoglycemia
What is a dangerous level of A1C?
When levels rise to 9.0, the risk of kidney and eye damage and neuropathy increases. Some people who are newly diagnosed could have levels over 9.0. Lifestyle changes and possibly medication can lower levels quickly. For someone who has long-standing diabetes, levels rise above 9.0 could signal the need for a change in their treatment plan.
Some labs estimate average blood glucose (eAG), which corresponds to home glucose meter readings (mg/dL), allowing patients to understand the results better.
Why is my A1C high?
As blood sugar level rises, so do A1C levels. “A high A1C indicates that blood sugar control is not optimal. This in itself is not an emergency, but it gives your healthcare provider a picture of how blood glucose has, or has not, been controlled,” says Dr. Williams.
Poor diabetes control or a need for medication adjustments might cause higher A1C. Diet changes, daily exercise, or medication adjustments might quickly lower A1C. Because Type 2 diabetes is a progressive disease, adjustments to one’s treatment might be a part of the process of controlling diabetes. Poor diabetes control does not always mean a patient is doing something wrong. But there are other reasons why levels might be high.
As previously mentioned, other health conditions can cause skewed results. These include kidney disease, anemia, liver disease, asplenia, blood loss, hypothyroidism, uremia, and sickle cell anemia. Other factors that might lead to a high A1C level include increased age, pregnancy, and gestational diabetes.
Can you have high A1C and not be diabetic?
According to one 2009 study, 3.8% of people without a history of diabetes have an elevated A1C level (over 6.0). This group is more likely to have other risk factors for Type 2 diabetes and cardiovascular disease. Researchers found that the following groups were more likely to have an elevated A1C without having a diagnosis of diabetes:
- Non-Hispanic black and Mexican American
- Higher C-reactive protein levels
A high A1C result might signal that there is a problem. “Even a modest increase in your blood sugar, above normal levels, can increase your risk of heart disease, even when you don’t have full-blown diabetes,” says Dr. Bellatoni. A physician can review test results and talk to patients about risk factors and lifestyle changes to improve blood sugar levels.
How to lower your A1C levels
“It’s important to get your hemoglobin A1C levels as close to normal as possible,” says Dr. Bellatoni, “Decreasing your hemoglobin A1C decreases your risk of having complications from diabetes. Even if you cannot get your A1C back to the normal range, any improvement lowers your risk of diabetes complications.”
Diabetes tracking and treatment
- Follow your diabetes treatment plan: Understand the treatment plan before leaving the healthcare provider’s office and discuss barriers (emotional, physical, financial) that could prevent you from following the program. Attend all follow-up visits.
- Consistently take prescribed medications: If a healthcare provider has prescribed medications to reduce blood sugar levels, take them regularly. Some people only take medication when they aren’t feeling well, but these medications don’t work unless taken consistently.
- Monitor and track blood sugar: Regular blood sugar monitoring is the most important step in diabetes management, according to the CDC. Healthcare providers can inform patients of different types of meters and help patients find the best one for them. Providers can also tell patients how often to check their blood sugar and what their target blood sugar range is. Keep a log of your blood sugar levels to look for patterns and triggers for blood sugar spikes and lows. If you wear a continuous glucose monitor, you can use the data. Learning what causes blood sugar to rise or decrease can help you create a plan to keep it consistent.
- Weight loss: You might not need to lose as much weight as you think. A study published in 2019 found that people with Type 2 diabetes who reduced their body weight by 10% within five years of their diagnosis achieved remission from the disease. Work with a healthcare provider to come up with a weight loss goal. Work with a nutritionist or dietitian to help create a feasible meal plan.
- Plan grocery shopping and meals: Eating on the go often involves foods that are unhealthy. Take time to plan meals and use those to create a healthy grocery list.
- Don’t skip breakfast: A study published in the journal Obesity found that people who ate a large breakfast rich in protein and fat helped reduce A1C and blood pressure.
- Eat a healthy diet with proper portions: Aim for half of your plate to be low-starch vegetables, one-fourth lean protein, and one-fourth whole grains. Blood sugar levels can increase if you eat more than your body needs. Use food scales and measuring cups and spoons to make sure portions are appropriate.
- Monitor carbohydrate intake: Eat carbs that have high fiber and nutrients, such as whole grains, whole fruits and vegetables, and legumes. Avoid carbs like candy, cakes, white bread, rice, and pasta.
- Stick to a meal schedule: Some people with diabetes find it best to eat at the same time each day. Certain diabetes medications or insulin can cause blood sugar to drop too low if you skip a meal, according to the NIDDK. Talk with a healthcare provider if you aren’t sure what the best meal schedule is. A nutritionist, dietitian, or certified diabetes educator (CDE) can help you find the right diet.
- Exercise regularly: Both aerobic and resistance training help to reduce glycemic control, according to a study published in 2016. Exercise improves blood glucose control, reduces cardiovascular risk factors, contributes to weight loss, and improves wellbeing. For people with prediabetes, regular exercise might prevent or delay Type 2 diabetes development.
- Keep moving: Keeping active makes the body more sensitive to insulin, according to the Centers for Disease Control and Prevention (CDC). Although regular exercise is important, daily activity is also considered moderate-intensity physical activity. Daily activities include gardening, walking, dancing, mowing the lawn, swimming, and even doing housework.
- Consider supplements: There is limited research into whether supplements and herbs can help lower blood sugar. For example, a review published in 2013 tested aloe vera for diabetes in rats and found it might help. Additionally, a study published in 2017 found people with prediabetes who used powdered fenugreek seed were less likely to receive a diagnosis of diabetes. And although the evidence is conflicting, a meta-analysis conducted in 2013 found consuming cinnamon significantly decreased glucose. The ADA doesn’t recommend cinnamon to reduce glucose, and it shouldn’t be a first-line treatment. Always talk to a healthcare provider before taking supplements.
- Use stress management tools: A study published in 2018 found that using mindfulness to reduce stress resulted in decreased A1C levels as well as increased wellbeing and general health.
- Avoid denial statements: Denial can take many forms, according to the ADA. Avoid saying (or thinking) things like, “One bite won’t hurt,” “I don’t have time to eat healthy today,” or “My diabetes isn’t serious.”
- Connect with other people who have diabetes: Feeling alone can make it more challenging to stick to a treatment plan. Find an in-person support group or look for one online. Connecting with other people who are in a similar situation can offer support, guidance, and accountability.
Remember, A1C tests measure blood sugar levels over three months. Lifestyle and diet changes take several months before making a meaningful impact.