The A1C test is used to diagnose type 1 and type 2 diabetes. Your A1C score tells you what percentage of a protein in your blood called hemoglobin is coated in glucose. Glucose is the sugar in your blood.

Hemoglobin is the protein that carries oxygen throughout your body.

This test is superior to other blood glucose tests because it isn’t strongly influenced by how long ago you ate or what you ate recently, unlike the typical blood tests done at home. Instead, the test gives a better indication of your current health based on information from a longer period of time.

Red blood cells live for about four months. For that reason, the amount of glucose coating your hemoglobin indicates your average blood sugar level for the past three to four months.

After diagnosis, the A1C test is used to measure how well a person is managing their diabetes. The test is also known as the glycated hemoglobin, glycohemoglobin, estimated glucose average, glycosylated hemoglobin, hemoglobin A1C, Hb1C and HbA1C.

What Does Each Score Mean?

High A1C scores are correlated with diabetes. A higher A1C level indicates that you have poor blood sugar control and that you’re at risk for diabetes complications. That’s because the higher the percentage of your hemoglobin that is coated with glucose, the poorer job your insulin hormone is doing of removing glucose from your blood.

The basic way to interpret your A1C score is in three categories: normal, prediabetes and diabetes. These are the categories your doctor will use to make a diagnosis.

A score below 5.7 percent is normal, a score between 5.7 percent and 6.4 percent is an indicator of prediabetes and a score of 6.5 and above means that you have diabetes. Physicians will usually repeat the test a second time on a different day before diagnosing diabetes. Initial tests are often used for comparison.

Granted, this is an initial system of classification. There are additional steps you should take based on where your score lies within those ranges.

Read the guide for your specific score for a step-by-step guide on how to avoid or diminish the effects of diabetes based on your blood sugar level, as determined by the A1C test.

Higher A1C Scores

A higher A1C level indicates that you have poor blood sugar control and that you’re at risk for diabetes complications. That’s because the higher the percentage of your hemoglobin that is coated with glucose, the poorer job your insulin hormone is doing of removing glucose from your blood.

A score of 8 percent is common for people who have had diabetes for a long time but haven’t taken action to treat it. If you have this score, you should begin treating your diabetes through medical and nonmedical channels.

Once your score is above 9 percent, you should immediately seek medical attention to reduce the glucose in your bloodstream. A 9 percent A1C score can be dangerous. If you’ve tested this high, you should not attempt to remedy your blood glucose levels independently. At this point, the glucose that has attached to your hemoglobin has thickened your blood considerably. Your blood is supposed to be thin so that it can travel through your blood vessels. Your heart has to put in extra effort to carry this thick blood to and from your heart.

As your A1C level increases above 10 percent, you’ll be at serious risk of kidney failure, blindness, stroke, heart attack and more. Additionally, when your A1C level is greater than 10, the Department of Transportation (DoT) no longer allows you to have a commercial driver’s license. If your score is higher than 10 percent, seek immediate medical care.

Lower A1C Scores

Hypoglycemia is low blood sugar or low blood glucose. When you have hypoglycemia, it's easier to determine with a blood glucose test than with an A1C score. A hypoglycemic blood glucose score is an A1C score below 4 percent or a blood glucose score of 70 or less.

When you have diabetes, you are at risk for hypoglycemia. Hypoglycemia is a side effect of insulin and other types of diabetes medicines that cause your body to produce more insulin than it should be.

It can be severe or mild. Mild hypoglycemia is characterized by anxiety, sweating, fatigue, an irregular heart rhythm, hunger, irritability and tingling sensation around the mouth. You may also have paler skin.

When it is severe you might be unable to treat yourself. In extreme conditions, hypoglycemia is characterized by confusion, blurred vision, seizures and loss of consciousness.

Treatment of hypoglycemia involves quickly stimulating your glucose levels back into the normal range by eating foods and beverages with high amounts of sugars.

It usually occurs when you haven't eaten for a long period of time; however, it may also appear after eating. Sometimes, after eating, your body produces too much insulin and that can cause hypoglycemia too.

Interpreting Your A1C Score

Blood glucose scores are measured in milligrams per deciliter or millimoles per liter. When an A1C score is converted to this measurement, the score is known as an eAG.

Your eAG score is the average of your blood glucose scores over the last three to four month, but it is not going to be equal to the average of every time you've checked your blood glucose on your monitor over that timeframe. That's because, typically, patients are more likely to check their blood glucose scores when they're nervous about what it will be (i.e. when it is low).

Most people are more familiar with the scores on their blood glucose score than they are with A1C scores. If it's easier for you to understand, the chart below converts your A1C score to your eAG score, which is also known as your average glucose. See the break down below of the conversion.

What to do After Checking Your A1C Score

It's important to continue monitoring your A1C score if it indicated that you have prediabetes. You should check your A1C score again in six months to see if the actions you've taken have reduced your blood sugar or if you are closer to a diabetes diagnosis. A score that rises indicates that you'll need to take strong action to change directions or risk getting diabetes.

People that were diagnosed with diabetes but have a consistent blood sugar level in the target range without the help of insulin should also check their A1C scores once every six months.

People that use insulin to manage their diabetes and have a blood sugar level that falls out of the target range should check their scores once every three months. Monitoring for changes can help alert you when your health is at risk and inform you about whether the corrective actions you're taking are working. Doctors do their best to provide you with effective medicines, but the A1C test is your best option for finding out if the medicine you're taking is working or if it needs to be changed.

If your A1C test indicated that you have diabetes, you should aim to lower your score to get it into a manageable range. For people with diabetes who are under 19 years old, you should aim to lower your A1C score to 7.5 percent. For people with diabetes who are older than 19, you should aim to have an A1C score of 7 percent or less.

How to Lower Your A1C Score

People who are close to developing prediabetes, are at risk for diabetes or who have dangerously high A1C scores can benefit from lowering their A1C scores. The tips for decreasing the glucose that's attached to your hemoglobin are tips that can improve your overall health as well.

1. Limit the calories in your diet

Reducing the calories in your diet to somewhere between 1,200 and 1,500 will help reduce your A1C score over time. It will take a few months to see large scale results because your A1C score is accounting for your diet over the past four months. Therefore, your actions from three months ago will impact your score today.

Reducing the calories in your diet will help you to lose weight. When you've got high amounts of fat in your body, it causes your blood to resist insulin. The more fatty tissue you have in your body, the more difficult it is for insulin to travel through your body and remove glucose from your blood cells.

2. Work out more frequently

Working out makes your cells more sensitive to insulin. That means your body is better able to remove the glucose from your blood cells. Additionally, physical activity can help you lose weight. When you lose weight, you decrease the fat within your body making it easier for the insulin to get to your blood.

Exercise causes your body to use up the glucose in your body as energy, as well.

Even if you're not interested in working out, it's important that you don't become inactive. When you're not active, your body needs to work harder to remove the glucose from your bloodstream. At the minimum, make sure you move about every day.

3. Decrease the bad cholesterols and increase the good cholesterols in your body

You want to at least have half as many good cholesterols as bad cholesterols. Good cholesterols are known as HDL and bad cholesterols are known as triglycerides, which is a type of fat carried within your blood.

When you don't have the right ratio of good to bad triglycerides, the triglycerides will clog your bloodstream. A clogged bloodstream makes it difficult for insulin to travel to your blood cells to remove glucose. When you have a higher proportion of triglycerides to HDL, you have a higher chance of type 2 diabetes.

4. Get the right amount of sleep each night

According to Harvard's Dr. William Kormos, you should sleep at least seven hours every night.

When you don't sleep enough, your body produces more ghrelin. Ghrelin is a hormone that stimulates your appetite. Too much ghrelin can cause you to overeat and, thus, gain weight. Sleeping less than seven hours a night is associated with increased obesity. As mentioned above, increased fat within your body makes it difficult for insulin to effectively remove glucose from your bloodstream, which would, in turn, increase your A1C score.

5. Avoid high levels of stress

Heightened stress levels cause your body to produce less insulin. Your body wants to ensure that you have all the glucose you need to serve as energy in the situation. It takes 6-8 hours for your body to start producing insulin again. That leaves your body to have to deal with heightened glucose levels on its own.

More so, when you're stressed, growth hormone and cortisol levels rise. Your brain triggers the release of the cortisol hormone from your adrenal glands in response to stress. Cortisol and growth hormone cause your body's tissues to be less sensitive to insulin. Both hormones can take 6-8 hours to stop affecting your body.

6. Drink less alcohol

To reduce your A1C score, you might consider drinking less alcohol. Particularly, you should avoid sugary mixed drinks, which will raise your blood sugar.

Additionally, alcohol can reduce your liver's ability to produce sugar, which can cause low blood sugar or hypoglycemia.

At the very least, consult with your doctor about your alcohol habits as soon as possible. Alcohol may interact negatively with your current medications. Your doctor may be able to switch the medicines you are taking to ones that are less affected by alcoholic beverages.

How Accurate are A1C Scores?

You can use your A1C score to track the progress of your actions. Your blood glucose is more heavily affected by your day-to-day activities.

Your A1C score, however, gives a better picture of your health over a time. It's less affected by what you had for lunch today and more affected by whether you've been consistently following better eating, exercise, stress or sleep habits. Therefore, your blood glucose test might indicate you have diabetes, whereas your A1C score might not.

A1C scores are accurate up to .5%, so if you’ve scored a 6.89 percent, your actual score can be anywhere between 6.39 percent and a 7.39 percent. This is why doctors will test your A1C score twice before diagnosing you with diabetes – they want to make sure the reading is accurate.

There are a few common reasons why your A1C score will have errors or misreadings.

  • Patients who experience chronic bleeding may experience faulty low scores because of a loss of red blood cells.
  • Patients who have iron deficiencies or anemia may experience A1C scores that are falsely high as a result of not having enough healthy red blood cells in the body.
  • Patients who are African, Southeast Asian or of Mediterranean descent tend to find inaccuracies in their A1C tests. People who fall within these groups are more likely to produce a hemoglobin variant different than the typical hemoglobin A, which causes the inaccuracies. An example of a hemoglobin variant is present in people who have sickle cell disease, which changes the lifespan of red blood cells.
  • Patients who are going through hemodialysis might have false lows because the processes may be filtering the glucose out of the patient’s bloodstream.
  • Patients who have had a recent blood loss due to surgery or a heavy menstrual cycle may experience a false low.
  • Liver disease and kidney failure can cause your reading to be inaccurate.
  • The test is not as accurate for pregnant women because red blood cells do not live as ln in their bodies.

Additionally, your A1C percentage can be off by as much as half a percent based on the margin of error. While that might mean the difference between being diabetic and prediabetic, if you’re a half a percentage away from developing diabetes or prediabetes, you should make changes to your lifestyle to reduce your score.

Purchasing the A1C test

The A1C test is covered by most insurance plans for two or three times per year in the doctor's office. Sometimes, insurance plans require that you wait a certain length of time between each test. It's important that you clarify these details prior to getting your tests done.

If you need tests done more frequently than your insurance allows, you can get the test at most drug stores for less than $50. These tests need to be administered from home.

At doctor's offices, you typically get instructions before taking a test. Whether you're at the doctor's office or taking the test from home, when you take the A1C test you don't need to do any advanced preparation.

Nonetheless, you may be asked to fast before taking the test at your physician's office. The reason for this is that at the doctor's office you will likely be taking other tests at the same time. In which case, those tests may require you to have an empty stomach.