HbA1c, Glycated Hemoglobin

The HbA1c blood test measures your average level of blood sugar over the past 90 days. It is also called glycated haemoglobin because most monosaccharides (simple sugars), such as glucose and fructose, spontaneously bond with the haemoglobin to ‘glycate’. The higher the glucose levels in the blood, the more it sticks to or binds with the haemoglobin, and the higher is glycated haemoglobin or HbA1c level in the blood. 

One of the reasons why the HbA1c test is done is to know whether a person is prediabetic or prone to diabetes. Accordingly, the person can take appropriate action to prevent diabetes to a certain extent; this includes  measures like reducing fat and sugar intake,  exercising regularly, and losing weight . No matter whether you are prediabetic or diabetic, knowing the HbA1c test range is a must.

HbA1c Test Range

Below 5.7% - Normal
Between 5.7% to 6.4% - Prediabetes 
6.5% and above - Diabetes

Who should get the HbA1c blood test done?

• People with a family history of diabetics 
• People who are suffering from diabetes
• People who have been diagnosed borderline diabetic or Prediabetic
• People having recurrent infections, especially skin infections and urine infection
• People with high Cholesterol levels
• Overweight people

Medically reviewed by Dr Shakti, General Physician/Internal Medicine at Indraprastha Apollo Hospitals, New Delhi

Frequently asked questions

How is the blood sample taken?

To take the blood sample, a tourniquet (elastic) band is placed tightly on the upper arm. The patient is asked to make a fist. This helps in the buildup of blood filling the veins and it becomes easy to collect the blood. The skin is cleaned before inserting the needle in the vein in order to prevent bacteria from entering. The needle is then inserted into the vein in the arm and the blood sample is collected in the vacutainer.

What conditions or diseases can affect the results of the HbA1c test?

The conditions or diseases which can affect the results of the HbA1c test include anemia, supplements such as vitamin C, E, and high cholesterol levels. Having kidney or liver disease can also affect the results of HbA1c. The presence of abnormal hemoglobins or hemoglobin variants like sickle cell disease, thalassemia can also affect the results.

What does HbA1c test measure?

The HbA1c test measures the levels of glucose which is bound to hemoglobin in the red blood cells. When the levels of glucose in the blood become high, the glucose binds to the hemoglobin. The life of red blood cells is three months. Thus, the HbA1c test measures the average level of glucose for the past three months in the blood.

What is diabetes?

Diabetes occurs when the levels of blood glucose (sugar) become too high. Blood glucose is the main source of energy and is derived from the food which is consumed. Insulin is a hormone which is produced by the pancreas. Its function is to help derive glucose from food and deliver it to cells so that it can be used for energy. When the body doesnt produce enough insulin or is not able to use the insulin well, the glucose levels rise due to abnormal regulation of insulin in the body which leads to diabetes.

How does diabetes affect the body?

Diabetes affects major organs of the body which include the heart, blood vessels, nerves, eyes, and kidneys. Uncontrolled blood glucose levels can cause damage to these organs and create complications if the blood glucose levels are not controlled. The complications can even cause disability in the body and can be life-threatening as well.

How does diabetes affect the body?

Diabetes affects major organs of the body which include the heart, blood vessels, nerves, eyes, and kidneys. Uncontrolled blood glucose levels can cause damage to these organs and create complications if the blood glucose levels are not controlled. The complications can even cause disability in the body and can be life-threatening as well.

What does the term Hyperglycemia refer to?

The term Hyperglycemia refers to high levels of glucose than the normal range in the blood.

What are the signs and symptoms of Hyperglycemia?

The signs and symptoms of Hyperglycemia include blurred vision, increased thirst, frequent urination, fatigue, and headache. If not treated, the signs and symptoms of hyperglycemia can worsen and the person might have nausea, vomiting, fruity-smelling breath, shortness of breath, dry mouth, weakness, confusion, pain in the abdomen, and coma.

What does the term Hypoglycemia refer to?

The term Hypoglycemia refers to low levels of glucose than the normal range in the blood.

What are the signs and symptoms of Hypoglycemia?

The signs and symptoms of Hypoglycemia include fatigue, shakiness, irregular or fast heartbeat, pale skin, shakiness, sweating, anxiety, hunger, irritability, tingling, or numbness of the lips, tongue, and cheeks. If not treated, the signs and symptoms of hypoglycemia can worsen and the person might feel confused, experience blurred vision, seizures, and loss of consciousness.

Should I inform my doctor if I am taking any medicines?

Yes, please inform your doctor if you are taking any medicines or supplements as it might interfere with the test results.

What are the variables which can affect HbA1c test results?

HbA1c levels can get affected if you have any blood related disorders like sickle cell anaemia or pernicious anaemia. Ingestion of some particular medications, vitamin C and alcohol may affect the actual HbA1c test values. It is therefore recommended to have proper consultation with the doctor before going for this test.

What is hypoglycemia?

Hypoglycemia occurs when the blood has less than normal sugar in the body. Often, it  leads to dizziness, nausea and fainting. In such a situation, one should immediately consume sugar-rich items like candy to balance out the glucose requirement of the body.

What is hyperglycemia?

Hyperglycemia occurs when there is a spike in blood glucose levels. It is sometimes life-threatening and an immediate consultation with your doctor becomes necessary to normalise the blood glucose level.