Many people have diabetes globally. The American Diabetes Association has recommended glycated hemoglobin (HbA1c) as a diagnostic test for diabetes. It is considered a reliable measure of blood sugar as it reflects the cumulative glycemic history of the past two to three months.
Hemoglobin is the iron-containing molecule within the red blood cells. They are responsible for carrying oxygen to the body tissues. A small percentage of hemoglobin gets attached to sugar or glucose molecules; this type of hemoglobin molecule is known as hemoglobin A1c. This hemoglobin A1c depends on the blood glucose levels; the highe the glucose level, the higher the A1c molecules in the blood.
This article helps you to understand more about the hemoglobin A1c test, normal A1c levels, and more.
What is Hemoglobin A1c?
Hemoglobin protein molecules are present inside red blood cells; it helps to carry oxygen to the cells of your body. When sugar enters your bloodstream, it gets attached to the hemoglobin in your red blood cells. Everybody has glucose molecules attached to the hemoglobin, but people with diabetes have more such molecules. Hence hemoglobin gets glycosylated, and it is known as hemoglobin A1c or HbA1c (1).
Hemoglobin A1c can help to measure blood glucose levels. If a person’s blood glucose level is higher, then he will have more hemoglobin A1c molecules. As red blood cells live for an average of 3 months these glucose molecules reflect in the bloodstream for about 2 to 3months.
A blood test can measure the amount of hemoglobin A1c in the blood. This test shows the person’s average blood sugar levels for 2 to 3 months before the test; hence, this test would help the physician understand how well a person’s diabetes is being controlled.
What is an A1c Test?
Usually, people with diabetes depend on urine tests or daily finger-prick tests to measure their blood sugar levels. Although this test is accurate, it would be momentary. This is because your blood glucose keeps changing based on your diet, physical activity, and hormonal changes. For example, your blood sugar would be high in the middle of the night, and you will be unaware of it.
The A1c test was available from the 1980s and is playing a vital role in monitoring diabetes and in helping to control it. A1c measures the average blood glucose for 2- 3months, so it helps to track if you have a high fasting blood glucose or after food blood glucose, even when your overall blood glucose is normal (2).
A1c test is the most recommended test for pre-diabetics and diabetics because it doesn’t require fasting, and this test can be done any time as a part of overall blood screening. It is also known as the HbA1c test, hemoglobin test, glycohemoglobin test, or glycated hemoglobin test (3).
Who Should Get an A1C test?
A1c test is recommended :
1. To diagnose prediabetes
If you have prediabetes, regular monitoring of your glucose level is essential because you are at high risk of developing diabetes and cardiovascular diseases.
2. To diagnose type 1 and type 2 diabetes
Your doctor may recommend an A1c test if you have type 1 or 2 diabetes; it is advised to monitor the average blood glucose levels.
The initial test results of A1C will act as a baseline for the treatment plan; the subsequent or the regular A1C test helps to monitor your diabetes progress and review the treatment plan.
Your healthcare provider can recommend A1C tests based on the type of diabetes, your treatment plan, how well your blood glucose level is controlled and maintained. For example, your healthcare provider may suggest A1C test :
- Once every year for prediabetes patients
- Twice a year for type 1 and 2 diabetes if your blood sugar level is consistently within the target range
- Four times a year for patients under the administration of insulin; if their blood sugar levels are varying abruptly or not in the target range
- If there is any change in your diabetes treatment plan or planning new medications
- If you are aged 45 and above, even if your results are normal. If you have any risk factors or if you have gestational diabetes then repeat the A1C test every 3 years (4)
How Is Hemoglobin A1c Measured?
The hemoglobin A1c test depends on the chemical charge on the molecule; because HbA1c has a charge that differs from the charge on the other hemoglobin molecules. The HbA1C molecule also differs in size from the other components.
When you give your blood sample for analysis, HPLC (High-pressure liquid chromatography) is performed to separate the HbA1C molecules from normal hemoglobin molecules based on charge and size (5).
The advantage of the HbA1C test is that it is not affected by short-term fluctuations in blood glucose concentrations, for example, due to diet, and hence you can have blood anytime. Fasting for the blood test is not necessary for the HbA1c test.
What Are Normal Levels of Hemoglobin A1c (Chart)?
The HbA1C levels are less than 5.7% of total hemoglobin in healthy individuals. A level of 6.5% of total hemoglobin implies that diabetes is present. Many studies suggest that if you maintain the blood glucose levels below 7%, it can reduce the risk associated with diabetes and can be delayed or prevented.
Chart for normal diabetes and prediabetes HbA1C levels.
| |
HbA1C levels |
| Normal |
Below 5.7% |
| Prediabetes |
5.7% to 6.4% |
| Diabetes |
6.5% or above |
HbA1c chart
There are no guidelines to use hemoglobin A1c test levels as a screening tool. However, it helps the physician and healthcare providers to get a good idea of a patient’s diabetic graph.
The table explains to you the average blood glucose and A1c levels:
| Sl no |
A1C |
Mean blood sugar (mg/dl) |
| 1 |
6 |
135 |
| 2 |
7 |
170 |
| 3 |
8 |
240 |
| 4 |
9 |
275 |
| 5 |
10 |
275 |
| 6 |
11 |
310 |
| 7 |
12 |
345 |
According to the American Diabetes Association, your HbA1c levels should be less than 7.0%, whereas the American Association of Clinical Endocrinologists suggests that it should be less than 6.5%. In 2016, the ADA advised that if your A1c level is 6.5% and above then you are diagnosed with diabetes (6).
Experts suggest that there is a 10% decrease in the microvascular complications for every 1% decrease in A1c levels. Hence it is crucial to monitor your HbA1c levels.
What Can Affect Your A1C Results?
You can get an A1C test done additionally to the regular blood sugar self-test if you already have diabetes, but you cannot rely only on the A1c test because several factors influence increase or decrease levels in A1c.
If you have any chronic kidney disorders, anemia, blood loss, blood transfusion, early or late pregnancy, and liver problems, your A1c values will increase and give us a false result. If you have sickle cell anemia, chronic blood loss, or thalassemia, it will decrease your A1C levels.
When Should Hemoglobin A1c Levels be Tested?
In addition to the random fasting blood glucose levels, HbA1c levels monitoring is advised for type 1 and type 2 diabetes people. Higher the concentration of the HbA1c levels, the higher the blood glucose concentration. Your healthcare provider may suggest taking an HbA1c test to analyze your diet, exercise, and drug therapy on blood glucose with diabetes people.
How can HbA1c Help to Prevent or Control Diabetes?
The following tips may help you maintain your HbA1c levels and prevent diabetes in pre-diabetes. It helps to control type 1 and type 2 diabetes by;
- following the right diet,
- physical activity such as exercise, yoga,
- medications,
- And a combination of these
A normal or slight elevation in the HbA1c levels is a clear indication that your blood glucose level is under control. If your HbA1c increases despite your dietary plans and treatment, you must seek medical help. Your healthcare provider may suggest changing your treatment plan.
Final Words
Tracking your HbA1c levels helps you and your healthcare provider determine how well you can control your blood sugar levels over time. Although this cannot substitute your daily glucose monitoring methods, it helps you track your blood glucose levels for an average of 3 months. HbA1c test is a valuable tool that can help fight against diabetes and other blood glucose-related disorders.