- How A1C Test Works
- A1C Screening Test
- A1C Monitoring Test
- A1C and Blood Glucose
- Importance of A1C
- What to Do About a High A1C
How does the hemoglobin A1C test work?
The hemoglobin A1C is a test that measures your average blood sugar for the past three months. This test goes by other names, including glycated hemoglobin, glycosylated hemoglobin, or HbA1c.
If you have diabetes, your doctor may use the A1C to check how well you are controlling your blood sugar. A high hemoglobin A1C may mean that your treatment plan needs revision. The A1C is also used to diagnose diabetes or prediabetes.
Hemoglobin is the protein that gives red blood cells their color. Its job is to carry oxygen to all the cells in your body. As red blood cells travel around the body, glucose in the bloodstream attaches itself to the hemoglobin. The A1C test measures how much glucose is attached. Since red blood cells live around three months, the A1C test shows how high your blood sugar has been for the past three months.
A1C as a screening test
Combined with other indicators, the A1C can screen for both type 1 and type 2 diabetes. Type 1 diabetes usually develops during childhood or young adulthood. No one is certain what causes it. Type 2 usually develops later and has certain risk factors. You are more likely to develop type 2 diabetes if you:
- Are over 45 years of age
- Are overweight
- Lead a sedentary lifestyle
- Have a parent or sibling with diabetes
- Had diabetes during pregnancy or had a baby weighing over 9 pounds
If you are being screened for diabetes, your A1C results will fall into one of three categories:
- Less than 5.7%: normal, not diabetic
- 5.7% to 6.4%: prediabetic
- 6.5% or higher: diabetic
A1C as a monitoring test
If you have already been diagnosed with diabetes, your doctor may use the hemoglobin A1C test to monitor your blood glucose levels. A result of 7% or less usually means that you are controlling your diabetes.
Although less than 7% is a common goal, a higher reading may be better for some people. If you are prone to low blood sugar, also known as hypoglycemia, your doctor may prefer an A1C between 7% and 8%. A higher goal may also be better for those who have had diabetes for a long time or who have complications of the disease.
Difference between A1C and blood glucose
If you have diabetes, you may check your blood sugar at home. This test differs from the A1C. When you test your blood glucose, you are checking your blood sugar level at one moment in time. Your test result will reflect how long it has been since you ate something and the type of food you ate.
Home glucose testing gives you and your doctor information that the A1C does not. The A1C gives a blood sugar average but does not show whether your levels are steady or whether they go very high and very low. Your doctor needs both types of tests to understand how well you are controlling your blood sugar.
How accurate is the A1C?
Your doctor can do an A1C test using a blood sample from a finger prick. Called a point-of-care test, this test can be processed quickly. Your doctor may instead choose to take a larger blood sample and send it to a lab for processing. The results of the lab test may be slightly more accurate.
If you have recently had a blood transfusion, your A1C may not be accurate. Other health conditions can affect the red blood cells and result in inaccurate A1C results. These include:
Can you have a high A1C level and not have diabetes?
Yes. A high A1C level does not necessarily mean that you have diabetes. High A1C can be an early warning sign of prediabetes, for example. Still, the higher your A1C, the greater your risk is of developing type 2 diabetes, according to the CDC. The best way to know for sure if you have diabetes is to get the opinion of your doctor.
What causes high A1C besides diabetes?
Although a high A1C reading is often a sign of type-2 diabetes, it can be affected by other things that influence your hemoglobin levels. These could include:
- Certain medications, including steroids and opioids
- Receiving blood donations
- Anemia, or lack of iron
- High triglycerides
- Kidney, spleen, and thyroid disorders
Why the A1C is important
If you have diabetes, a high hemoglobin A1C means that you are more likely to experience complications. Some complications are serious. They include:
- Problems with eyesight
- Heart disease
- Kidney disease
- Nerve damage
Screening for diabetes is also important. Those with an A1C greater than 6% are at high risk of developing diabetes in the next 5 years. Identifying them is critical. Research shows that two interventions can lower their chances of developing diabetes. Lifestyle changes can reduce their risk by 50%. Using the drug metformin can reduce it by 30%.
What to do about a high A1C
After a high hemoglobin A1C, you and your doctor can work together to lower your numbers and reduce your risks. Your doctor may recommend a three-pronged approach combining education, diet, and exercise. Also, you may need to lose weight if you are overweight.
If you have type 1 diabetes, you will need treatment with drugs. Many of those with type 2 diabetes will require drug therapy as well.
What foods should I avoid if my A1C is high?
Some foods are more likely to raise your A1C blood sugar average over time. If you eat these foods consistently, your A1C is likely to stay high or go higher:
- Foods high in flour, including breads, rolls, and biscuits
What foods can bring my A1C down?
You can help lower your A1C blood sugar average by consistently eating the following foods:
- Beans and lentils
- Oats/Oat Bran
- Whole grain pasta
- Plain yogurt
Besides medication, what are other ways to lower my A1C naturally?
Watching your diet, including portion sizes and calories, can help you naturally reduce your A1C blood sugar average over time. Avoid foods that contribute to high blood sugar, especially sugary sodas, juice, and fruit drinks. Be conscious of healthy carb choices, like preferring beans and lentils over potatoes and rice. And get active! Getting regular, daily exercise is an essential component of overall health and helps promote lower blood sugar.
- Women's Gymnastics Brings High Risk for Concussion
- Going Solo: Masturbation May Give Humans an Evolutionary Edge
- Longer Breastfeeding in Infancy, Better School Grades for Kids?
- Kids With ADHD, Behavior Issues Have Poorer Trajectories as Adults
- FDA Finalizes Limit on How Much Arsenic Can Be in Apple Juice
- More Health News »
Health Solutions From Our Sponsors
Centers for Disease Control and Prevention: "All About Your A1C," "Diabetes Risk Factors."
Diabetes Care: "A1C Level and Future Risk of Diabetes: A Systematic Review."
Eyth, E., Naik, R. StatPearls, "Hemoglobin A1C," StatPearls Publishing, 2021.
Merck Manual Consumer Version: "Diabetes Mellitus (DM)."
Mount Sinai Hospital: "A1C test."
National Institute of Diabetes and Digestive and Kidney Diseases: "The A1C Test & Diabetes."
University of California San Francisco: "A1C Test."
American Diabetes Association: "Carb Counting and Diabetes."
Biochem J: "Interactions between insulin and exercise."
Top What Does It Mean When Your Hemoglobin A1C Is High Related Articles
Body Blood Sugar LevelsHigh blood sugar can be a sign of diabetes or prediabetes. The drugs that treat it sometimes cause low blood sugar too. WebMD helps guide you through the effects of both.
Diabetes (Type 1 and Type 2)Diabetes is a chronic condition characterized by high levels of sugar (glucose) in the blood. The two types of diabetes are referred to as type 1 (insulin dependent) and type 2 (non-insulin dependent). Symptoms of diabetes include increased urine output, thirst, hunger, and fatigue. Treatment of diabetes depends on the type.
Diabetes QuizTake the Diabetes Quiz and learn the causes, signs, symptoms, and types of this growing epidemic. What does diabetes have to do with obesity and diet? Learn about life as a diabetic.
Diabetes Symptoms in MenEarly symptoms of diabetes are different in men, such as low testosterone. In many cases, prediabetes that will progress to type 2 diabetes if it is not treated early.
Diabetes Symptoms in WomenDiabetes symptoms in women include vaginal itching, pain, or discharge, loss of interest or pain after having sex, polycystic ovarian syndrome (POS), and urinary tract infections or UTIs (which are more common in women. Symptoms of diabetes that are the same in women and men are excessive thirst and hunger, bad breath, and skin infections, darkening of skin in areas of body creases (acanthosis nigricans), breath odor that is fruity, sweet, or acetone, and tingling or numbness in the hands or feet, blurred vision, fatigue, tingling or numbness in the hands or feet, wounds that heal slowly, irritability, and weight loss or gain.
Complications of type 1 and type 2 diabetes are the same, for example, skin, eye, and circulation problems, low blood sugar (hypoglycemia), high blood sugar (hyperglycemia), ketoacidosis, and amputation. If diabetes is not managed a person may not survive.
Diabetes Treatment: Medication, Diet, and Insulin
The major goal in treating diabetes is controlling elevated blood sugar without causing abnormally low levels of blood sugar. Type 1 diabetes is treated with:
- and a diabetic diet.
Type 2 diabetes is first treated with:
- weight reduction,
- a diabetic diet,
- and exercise.
When these measures fail to control the elevated blood sugar, oral medications are used. If oral medications are still insufficient, insulin medications are considered.
Type 2 Diabetes Diet PlanA type 2 diabetes diet or a type 2 diabetic diet is important for blood sugar (glucose) control in people with diabetes to prevent complications of diabetes. There are a variety of type 2 diabetes diet eating plans such as the Mediterranean diet, Paleo diet, ADA Diabetes Diet, and vegetarian diets.Learn about low and high glycemic index foods, what foods to eat, and what foods to avoid if you have type 2 diabetes.
Hemoglobin A1c TestHemoglobin A1c or HbA1c is a protein on the surface of red blood cells. The HbA1c test is used to monitor blood sugar levels in people with type 1 and type 2 diabetes over time. Normal HbA1c levels are 6% or less. HbA1c levels can be affected by insulin use, fasting, glucose intake (oral or IV), or a combination of these and other factors. High hemoglobin A1c levels in the blood increases the risk of microvascular complications, for example, diabetic neuropathy, eye, and kidney disease.
Normal Blood Sugar Levels In Adults with Diabetes
People with diabetes can manage and prevent low or high blood sugar levels (hyperglycemia or hypoglycemia) by keeping a log of your blood sugar levels when you are eating and fasting and eat foods that are high in carbohydrates and sugar, for example, buttered potatoes, candy, sugary desserts, and fatty foods.
Blood tests, for example, the hemoglobin A1c test (A1c test) and urinalysis can diagnose the type of diabetes the person has. Diabetes during pregnancy, called gestational diabetes, should be managed by you and your OB/GYN or another healthcare professional.
Extremely high levels of blood glucose in the blood can be dangerous and life threatening if you have type 1, type 2, or gestational diabetes.
If you or someone that you are with has extremely high blood glucose levels, call 911 or go to your nearest Urgent Care or Emergency Department immediately.
To prevent and manage high blood glucose levels in people with diabetes keep a log of your blood sugar levels, eat foods that are high in carbohydrates sugar, for example, buttered potatoes, candy, sugary deserts, and fatty foods that you can share with your doctor and other healthcare professionals.
Prediabetes is a situation where a person's blood sugar levels are higher than they should be, but aren't high enough to be diagnosed with type 2 diabetes. There are no signs or symptoms of prediabetes. Some of the risk factors for prediabetes are
- high blood pressure,
- high cholesterol,
- heart disease,
- family history,
- poor diet, and
- lack of activity.
Diet changes along with other healthy lifestyle changes are important in treating prediabetes.
Diabetes: What Raises and Lowers Your Blood Sugar Level?Want to lower your blood sugar? Learn to better control your glucose levels by preventing blood sugar spikes and swings to avoid neuropathy and other diabetes complications. Find foods that lower blood sugar, and identify foods and activities that raise high blood sugar risks.
Type 1 DiabetesWhat is type 1 diabetes? There are new treatments for juvenile diabetes, and more people with diabetes can be treated than ever before. Learn the symptoms of T1D, the causes, and find ways to control your blood glucose levels naturally.
Type 2 DiabetesType 2 diabetes is a chronic condition that may be reversible with diet and lifestyle changes. Symptoms include excessive thirst, frequent urination, weight loss, fatigue, and an unusual odor to your urine. Most people don't know they have type 2 diabetes until they have a routine blood test. Treatment options include medications, a type 2 diabetes diet, and other lifestyle changes.
Type 2 Diabetes QuizWhat causes type 2 diabetes? Can it be prevented? Take this online quiz and challenge your knowledge of this common condition. Also, get the truth about myths and facts!
Type 2 Diabetes SignsLearn about type 2 diabetes warning signs, symptoms, diagnosis, and treatment options. Find out why thirst, headaches, and infections could be signs of diabetes. Discover the treatment options for people with type 2 diabetes, including medicines and lifestyle improvements.
What Is Hb H Disease?Hemoglobin H (Hb H) disease is an inherited hemoglobin disorder in which three out of the four alpha-globin genes that are usually present are deleted or has a mutation that impairs alpha-globin chain production. This leads to an excess of beta-globin chains that are unstable, precipitate within the cell, and destroys the red blood cells. Hb H is a thalassemia-like syndrome defined by hemolysis and the production of ineffective red cells.