How Is A1c Calculated. HbA1c Test Details

How Is A1c Calculated In the Lab or Doctor's Office

The hemoglobin A1C (HbA1C) level has become a critical diagnostic for the diagnosis and management of diabetes. In the long run, it can provide you with an indication of how effectively your diabetes treatment plan is working.

Diagnosing diabetes and monitoring the progress of a treatment plan is frequently accomplished through the use of the A1C test. The result is based on blood glucose levels over a three-month period, making it an excellent method for patients with type 2 diabetes or prediabetes. So Knowing how A1c is calculated matters. 

What is A1c?

A1C is a form of glycated hemoglobin, which is hemoglobin that has been bonded to glucose in the bloodstream. The most abundant protein in red blood cells is hemoglobin. The A1C level is formed as a result of the interaction between red blood cells and sugar in the bloodstream.

The higher the blood glucose levels are, the more glucose binds to hemoglobin, and the higher the amount of A1C in the blood. So, the A1C blood test measures the amount of hemoglobin that has been linked to glucose over time.

What is Hemoglobin in HbA1c?

Hemoglobin is a protein found in red blood cells that is responsible for transporting oxygen throughout the body. The process of glycation occurs when glucose levels are elevated and sugar molecules bond to hemoglobin, resulting in anemia. Once a hemoglobin molecule has been glycated, it will remain in that state in the blood until the red blood cell that carried it is withdrawn from circulation.

Given that a red blood cell has an average lifespan of 3 to 4 months, the A1C test is used to determine the status of blood glucose over the previous 3 to 4 months.

The results of the A1C test are expressed as a percentage. You have a higher average blood sugar level if your percentage is higher than the national average. An A1C result of less than 5.7 percent is considered normal.

You have diabetes if you have an A1C score of 6.5 percent or above on two different tests. A hemoglobin A1C score between 5.7 percent and 6.4 percent indicates that you have prediabetes and are at greater risk for type 2 diabetes and cardiovascular disease.

Your doctor will work with you to make lifestyle changes or prescribe medication to help lower your blood sugar levels if your A1C result is higher than the recommended range. The majority of people with diabetes monitor their blood sugar levels at home with a finger-stick test and a portable glucose meter or continuous glucose monitoring systems such as Dexcom or libre.

How To Interpret A1c Test?

Health care practitioners use the A1C test to determine how well patients are managing their diabetes over a two- to three-month period. It is a critical tool in determining how well patients are managing their diabetes. A1C levels, on the other hand, are expressed in two different ways: as a percentage or as an estimated average glucose (eAG) level (estimated average glucose level).

In order to compute the eAG, one must first take the A1C percentage and convert it to units of concentration, which are either milligram per deciliter (mg/dL) or millimoles per liter (mmol/L). For example, an A1C of 7 percent corresponds to an eAG of 154 mg/dL (8.6 mmol/L), whereas an A1C of 9 percent corresponds to an eAG of 197 mg/dL (11.0 mmol/L) of diabetes. Knowing your eAG can help you put your A1C in context and understand how your daily blood sugar levels related to your overall glycemic control, which is beneficial for the majority of people with diabetes.

What Does A1c Stand For?

The abbreviation A1c stands for "glycated hemoglobin." Hemoglobin, the oxygen-carrying protein in red blood cells, is a molecule that arises when glucose (blood sugar) builds up in your bloodstream and binds to hemoglobin. Diabetic complications are more likely to occur if your hemoglobin A1C level is higher than normal.

It is for this reason that controlling A1C levels is so crucial. It is the goal of the vast majority of diabetics to lower their A1C level down to 7 percent or below provided that how a1c is calculated is correct. When creating goals, it is necessary to take into consideration factors such as age and other health concerns.

As a general rule, younger people who do not frequently experience extreme low glucose, sometimes known as hypoglycemia, require lower objectives in order to avoid diabetic complications over the course of their lifetimes.

Patients who are older or who experience frequent low-glucose episodes may have a higher target glucose level. Consult with your healthcare team to determine what A1C level is appropriate for your situation. It is crucial to remember that the accuracy of A1C test results can be affected by a variety of circumstances. 

Can A1c Test Be Wrong?

Yes. The A1C test can be false or wrong in some cases even if the methods used to calculate A1c were correct. For example. A1C levels in persons with blood diseases such as sickle cell disease, thalassemia, or hemolytic anemia, for example, maybe lower than anticipated due to the shorter lifespan of their red blood cells in these conditions.

A1C values that are artificially high due to iron deficiency anemia, on the other hand, are associated with prolonged red blood cell longevity. Additional factors such as acute or chronic illnesses can have an impact on A1C levels.

In order to ensure that any relevant circumstances that may affect test results are discussed with a healthcare provider before the test is performed, People of African, Mediterranean, or Southeast Asian origin, for example, may have rare types of hemoglobin that cause falsely high or low hemoglobin levels to be detected.

Certain kidney and liver illnesses might impair the turnover rate of red blood cells, resulting in incorrect A1C measurements. Finally, recent blood loss or transfusion will also have an impact on the outcomes of the test. In spite of this, the A1C test is still believed to be a valid indication of long-term glucose management in patients with diabetes.

If you have any concerns about your test results, you should discuss them with your doctor. Thanks for reading. I hope this helped you understand more about how a1c is calculated for diabetes care. Please like, share, and comment on this topic below. Stay happy, stay healthy until the next blog post.

About the author

Dr. Ahmet Ergin is the author of The Ultimate Diabetes Book and the Founder of the SugarMD youtube channel. He practices in Port Saint Lucie, FL as an endocrinologist physician.