How to measure A1C levels in blood and what do they mean

The A1C test, also known as glycated hemoglobin, glycosylated hemoglobin, and hemoglobin A1C or HbA1c, is a commonly prescribed blood test to diagnose type 1 and type 2 diabetes. For those with preexisting diabetes, this test is helpful in regularly monitoring and managing blood sugar levels. Here are a few basic things to know about the test, such as what it is, how to measure it, the various levels, and what they mean

What is the A1C test?

The A1C test is based on the attachment of glucose to hemoglobin, a crucial part of red blood cells, which carry oxygen to the rest of the body. The glucose produced in the cells binds itself to the hemoglobin. If a significant proportion of glucose gets attached to hemoglobin, the glucose level rises in the bloodstream. The A1C test measures the amount of hemoglobin attached to glucose. Then, it indicates the average blood glucose levels over the previous three months. The A1C levels are always in percentage.

How are A1C levels measured?

The A1C test is quite a simple blood test. There is no need for A1C test fasting, so one can eat regular meals and drink enough water and other fluids. Usually, healthcare providers do the test in either of the following ways:

• The most common way of performing the test is for a phlebotomist to take a blood sample from a vein and send it for analysis to the lab. 
• The second way is to obtain a blood sample, which is then tested through a machine for results that typically take a few minutes. This type of A1c testing is usually used to monitor sugar levels and determine whether the treatment plan works. It cannot be used for screening or diagnosing diabetes.

What do the various A1C levels mean?

The A1C test is quite a simple blood test. There is no need to fast for it, so one can eat regular meals and drink enough water and other fluids. Healthcare providers usually perform the test in either of the following ways:

• Numbers lower than 5.7% are considered normal A1C levels. 
• Between the range of 5.7% and 6.4% is considered the prediabetes A1C range.
• Higher than 6.5% means type 2 diabetes (or type 1 diabetes).

For those with preexisting diabetes, the A1C test result gives a fair idea of how well the blood sugar treatment and management plan are going. Usually, lowering high A1C levels involves:

• Taking prescriptions,
• Administering insulin,
• Monitoring blood sugar levels, and
• Making lifestyle changes like eating healthier and exercising.
  

With the A1C test, a healthcare provider can know whether the treatment plan needs to be adjusted.
Besides, for those with diabetes, A1C levels are only an average measurement of blood sugar over the previous few months. They have no final say on whether one lives a healthy lifestyle. Also, A1C keeps changing, with age and other factors constantly affecting it. Yet, it helps to know whether one needs to take steps to improve one’s diabetes management.

A1C and estimated average glucose (eAG)

Sometimes, some laboratories report the A1C results as a percentage and the corresponding estimated average glucose (eAG). Here is how eAG is calculated:

• The A1C percentage is converted to milligrams per deciliter (mg/dL) or millimoles per liter (mmol/L), the same units used in at-home glucose meters or glucometers. 
• Like A1C, eAG indicates the average blood sugar level over the previous three months.

For instance, if a person’s A1C level is 7%, their eAG will be 154 mg/dL (8.6 mmol/L). Similarly, an A1C level of 9% equals an eAG of 212 mg/dL (11.8 mmol/L). All test reports will come with automatically calculated conversions, so one does not have to worry about complex calculations. Also, the reports will directly say whether the eAG level is normal, prediabetic, or diabetic. If a test report does not indicate the eAG levels directly, one can consult their primary care doctor to understand the report better.

What are normal A1C levels?

For those without diabetes, the average A1C level must be below 5.7%. However, for those with diabetes, the average A1C level usually depends on their health goals and the level of access they have to diabetes management tools and medication. In such situations, a healthcare provider can help determine the target goal for lowering the A1C levels.