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Hemoglobin A1c

Written by Ada’s Medical Knowledge Team

Updated on

Hemoglobin A1c (HbA1c) is a form of hemoglobin that is bound to glucose, a type of sugar we get from our food. This kind of hemoglobin can be used to determine your blood sugar levels over a longer period of time. Knowing your blood sugar helps with managing diabetes or knowing if you are at risk of developing the condition.

If you think your Hemoglobin A1c levels might be out of the normal range, try using the free Ada app to find out more about your symptoms.

What is Hemoglobin A1c?

Hemoglobin is a protein present in red blood cells that transports certain substances throughout the blood. Its main function is to carry oxygen from the lungs to the tissues and carbon dioxide from the tissues to the lungs. Besides that, hemoglobin can also transport other substances such as sulfide and nitrogen oxide, which are important base substances in certain medications.[1]

Hemoglobin can carry all these substances because it can bind to them, just like it can bind to glucose. Glucose is a type of sugar that can be found in your blood. This glucose comes from the food you eat and provides the body with the energy it needs. When hemoglobin is bound to glucose, it gets the name glycated hemoglobin, hemoglobin A1c or for short HbA1c.[2]

Why is HbA1c important?

HbA1c is very important for people who are at risk for diabetes or for those that have already been diagnosed with the condition. People with diabetes should have their blood sugar levels tested regularly to know the status of their condition. Unlike the blood glucose test, which measures the glucose at that exact moment, the HbA1c levels say something more about the glucose levels in the last few months.

This is because red blood cells with Hba1c in them can live up to 2-3 months. That way, the HbA1c levels give a better indication of the blood sugar level over a longer period of time, making the test more qualified to check if diabetes is actually under control. Managing diabetes is very important, because uncontrolled diabetes can have severe consequences such as eye and kidney disease.[2]

How to lower Hemoglobin A1c?

Hemoglobin A1c levels are expressed in percentages. The higher the percentage, the more glucose has been present in the blood for the past 2-3 months.

  • Under 5.7%: you’re in the normal HbA1c range.
  • Between 5.7 and 6.5%: you’re in the prediabetes range.
  • Higher than 6.5%: you’re in the diabetes range.

Regular physical activity can help reduce your HbA1c levels. Your diet is also crucial to lowering these levels. It’s important to eat regularly and to drink water instead of soda, juice or alcohol. You should also eat enough fruits and vegetables, while cutting back on sugars, saturated fats, trans fats and salt.

With some changes in lifestyle and diet, some people may avert developing diabetes if they’re still in the prediabetes phase. Others who already have diabetes may have more control over their condition and may avoid complications by adhering to a healthy lifestyle and diet.

In some cases, your doctor may also prescribe you medications that help get your hemoglobin A1c in the normal range.[3][4]

When should the HbA1c level be tested?

Getting a HbA1c test can help you with knowing your diabetes status. It can diagnose diabetes, but it can also give a clear indication on whether or not someone who has been diagnosed with diabetes has their condition well under control. Good management of diabetes can help prevent severe complications to the heart, kidneys and eyes. Other possible complications from diabetes are nerve damage, strokes, amputations and diabetic ketoacidosis (a life-threatening condition).

Besides this, the HbA1c levels can also indicate whether or not someone is at risk of developing diabetes. When someone is at risk, we call that stage pre-diabetes. In this stage, the blood sugar levels have been elevated for a longer period of time, but they aren’t yet in the diagnostic range for diabetes. People in this stage can often still prevent developing diabetes by making changes to their lifestyle and diet.[4][5][6]

People can often have prediabetes without having any symptoms. That’s why it’s important to keep the risk factors of diabetes in mind. If you recognize yourself in the following, you should get your blood sugar tested.

  • Being overweight
  • Being over the age of 45
  • Having close relatives with type 2 diabetes
  • Being of Hispanic or African descent
  • Having an inactive lifestyle.[^7]

Frequently asked questions

Q: How is HbA1c measured? HbA1c can be measured in the blood. It is often checked in a blood sample that has been collected from the arm, but it can also be measured in blood from a finger.

Q: Why is it important to check the HbA1c level? It’s important to know your HbA1c levels if you’re at risk for diabetes or to control your diabetes. By lowering your HbA1c, you can prevent complications.

Q: When do I need to seek medical help? If you think you are at risk for diabetes, then it would be useful to get your HbA1c levels checked. If you have already been diagnosed with diabetes, then it’s important to keep track of your HbA1c to prevent complications.


  1. Bianco CL, et al. (2018). Investigations on the role of hemoglobin in sulfide metabolism by intact human red blood cells. Accessed on 19 April 2022.

  2. Center for Disease Control and Prevention [CDC] (2021). All About Your A1c. Accessed on 19 April 2022.

  3. CDC (2021). Manage Blood Sugar. Accessed on 8 April 2022.

  4. NIDDK (2018). The A1 Test and Diabetes. Accessed on 20 April 2022.

  5. American Diabetes Association. Prediabetes. Accessed on 8 April 2022.

  6. CDC (2021). Prediabetes - Your Chance To Prevent Type 2 Diabetes. Accessed on 8 April 2022

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