The A1c test is a lab test that measures average blood sugar over the past 2–3 months. Used by healthcare professionals to diagnose and monitor diabetes, this test requires no fasting and is conducted by collecting a blood sample from the tip of the finger. Based on the test results, doctors can determine if the glucose concentration indicates normal, prediabetic, or diabetic levels. People can then evaluate their treatment plan for diabetes based on their target levels.

How does the A1c test work?

The red blood cells in the body contain a metalloprotein called hemoglobin, which helps carry oxygen from the lungs to all other cells of our body.

The sugar or glucose in the blood attaches itself to the hemoglobin and stays bound as long as the cells live. The higher the glucose level in the bloodstream, the more it will stick to the hemoglobin. This glucose-coated hemoglobin (or glycated hemoglobin) is called the hemoglobin A1c (HbA1c). The test measures the percentage of hemoglobin attached to the sugar and higher HbA1c levels indicate diabetes or at least, are a sign of increased risk of developing diabetes. The A1c test is also known as the hemoglobin A1c test, HbA1c test, glycated hemoglobin test, and glycohemoglobin test. It takes into account the blood sugar for a period of 3 months and calculates the result in the form of the average level.

Based on the test results, different levels of glucose—normal, prediabetic, and diabetic—are analyzed on an A1c blood sugar chart .

Understanding the chart

The blood sugar level charts are reference tools that give people a quick review of their test results. Based on this, patients and their healthcare providers can make a plan to ensure their glucose levels are in the safe range. The A1c blood sugar chart represents the glycated hemoglobin levels and indicates the risk of developing diabetic complications. It consists of numerical values for these levels and the estimated average glucose (or eAG). Consolidated readings help achieve a better understanding of diabetes as the eAG converts Ac1 data into the same units as home glucose meters. A1c levels are indicated as percentages, whereas eAG values are represented as mg/dL or mmol/L. Based on the test results, different levels of glucose—normal, prediabetic, and diabetic—are analyzed on an A1c blood sugar chart. Higher readings on the diabetes blood sugar chart indicate a greater risk of developing diabetes-related complications, so the chart is a useful tool for diagnosing prediabetes, type 1 diabetes, and type 2 diabetes. Further, doctors can utilize this information to monitor the patient’s glucose level, their progress, and the effectiveness of the treatment.

What do A1c levels mean?

The following guidelines are generally followed for examining A1c levels and analyzing the risks of diabetic complications:

For people who do not have diabetes or the complications of prediabetes, the normal HbA1c value should be below 5.7% (or within the range of 4–5.7%).

Values between 5.7% and 6.5% would suggest that the person is prediabetic and is at a higher risk of developing diabetes.

Values greater than 6.5% in the blood sugar level chart indicate the diabetic range, i.e., the person has diabetes.

Factors that influence target levels
Doctors recommend significantly different goals for both diabetic and non-diabetic people based on the guidelines. However, for people with diabetes, the target can vary depending on the acceptable A1c levels by age and other individual factors like:

Overall health

Whether they are pregnant

Complications (if any) due to diabetes

Duration of the condition

Prescribe treatment plans

Their treatment-related preferences and priorities

Accordingly, doctors may recommend HbA1c values under 6.5% for young patients with a long life expectancy, for those who have been diagnosed with diabetes recently, or for those who are otherwise healthy. Whereas, for older patients and those with a short life expectancy, people with the kind of diabetes that is hard to manage, or those with chronic health conditions, values in the 7–8.5% range would be recommended. The American Diabetic Association recommends an HbA1c level under 7% for adults with diabetes.

Test frequency
Doctors may ask people to undergo an A1c test to determine if they are prediabetic, or diabetic, or to determine if their glucose levels are stable. How often one needs the test depends on the amount of glucose as per the A1c blood sugar chart and the overall treatment plan. People with prediabetes can get the test done once a year. The ADA recommends undergoing the test at least two times a year for those who meet the treatment goals. Someone who takes insulin and has trouble maintaining the target levels may need to get tested 3–4 times a year, depending on their doctor’s recommendation.

Following the test, doctors might change the treatment plan for those with diabetes and/or recommend a combination of food regimen, exercise, and treatment to bring the blood sugar down. With changes in the treatment strategy, the frequency of A1c tests might increase.