The HbA1C test is a simple yet useful blood test that helps to diagnose and monitor blood glucose control in people suffering from diabetes. Also known as glycated haemoglobin or glycosylated haemoglobin, this potential test is an indicator that determines the increase and decrease in blood glucose levels that could have abnormally fluctuated over the last three months. Haemoglobin is a protein located in red blood cells of the body that effectively carries oxygen through the system. The levels of HbA1c are directly related to the amount of glucose in the blood. By measuring the amount of haemoglobin in the blood with glucose attached (of the last three months’ time) it helps to diagnose pre-pre-diabetes symptoms in people and the status of ongoing diabetes along with the effectiveness of its treatment. Since the red blood cells can survive in the body for up to four months, HbA1C testing can easily find out how much sugar the bloodstream contains over the past three months. The HbA1C test is different from the normal blood glucose test because the latter gives information on how much sugar is in the blood at that very moment whereas HbA1C provides an average of three months which becomes ideal in monitoring besides managing this chronic health disorder.

Also Read:  Diabetic Macular Edema: Causes, Symptoms And Treatment

Why Is HBA1C Done?

Since the test is an effective indication of blood glucose levels from the previous three months, physicians recommend that people with diabetes get HbA1c testing done frequently. This testing is done in addition to home blood glucose monitoring to check blood levels daily through a glucometer.  A raised level of A1C from the last 12 weeks correlates with an increased risk of developing diabetes in the case of a non-diabetic and complications such as diabetic retinopathy in the case of diabetic people. An HbA1C value higher than 6.5 implies one has diabetes.

Also Read: How to recognise signs of diabetic retinopathy

Test Procedure And Results Of HBA1C

A simple blood test, this testing does not require any special preparation. A sample of blood is taken by your doctor or at a pathology lab. As a matter of fact, unlike many diabetes-related tests, there is no need to fast while taking this test. One can go for it even after having taken a regular meal. HBA1C measures the percentage of haemoglobin that is stuck to glucose, which reflects the concentrated levels of average blood glucose or glycosylated haemoglobin. It can be measured in percentages or units of mmol. Both ways give accurate results which are available to the patient within 24 to 48 hours. A normal HbA1c result ranges between 3.5 to 6 per cent or 15-42 mmol.

Also Read: Diabetes Mellitus: Know Your Fasting, Post-Prandial, HBA1C Numbers

When Should One Get an A1C Test?

One should go for a baseline A1C test if:

• The result has already shown that you have prediabetes or diabetes
• You are over age forty-five, overweight, and have risk factors for getting type 2 diabetes
• Your result is normal, but you are over forty-five, are at risk due to hereditary factors, or have had gestational diabetes at some point in time

Does An Elevated HbA1C Confirm Diabetes?

It is not necessary that when HbA1C levels are high, one necessarily has diabetes. Certain causative factors can show raised or low HbA1c levels. For instance, just like our blood group types some of us have type A haemoglobin or adult haemoglobin, while some of us may be born with a completely different variant of haemoglobin. This is known as haemoglobinopathy and at times can cause inaccurately high or low HbA1c results. Moreover, some other factors such as iron deficiency, haemolytic anaemia, early or late pregnancy, blood loss, and chronic kidney and liver problems such as NAFLD, besides some ongoing medications or supplements during the time of testing like iron, folate supplements and Vitamin C, E and B12 supplements can create discrepancies in results. Nonetheless, HbA1C testing has been crucial in diagnosing mild to severe prediabetes and provides a reliable measure of chronic hyperglycaemia thus successfully helping the patient to manage diabetes and prevent the occurrence of comorbidities.

Frequently Asked Questions:

Should pre-diabetic patients need HbA1C tests?

Yes. Doctors recommend HbA1C for patients with borderline elevated blood sugar levels. Repeating this test every three months and being aware of the levels helps control blood glucose, with the help of dietary and lifestyle management, without medication.

What lab techniques are used in performing HbA1c?

Various labs use different analytical methods to measure Hemoglobin A1c. Labs use liquid chromatography to calculate the result as a ratio to total hemoglobin, and widely used techniques are immunoassay, enzymatic assay, capillary electrophoresis, or Boronate affinity chromatography (BAC).

How should one interpret the results of HbA1C?

The results may vary slightly depending on the technique and age of the patient. Persistent levels of elevated HbA1C are common among diabetic patients, but they may come down within the reference range in a person with reasonable control over glucose levels.

Here is how you read the results:

<5.7% is normal

5.7% to 6.4% is pre-diabetes

6.5% and above are diabetes

How often should one repeat the HbA1C test?

Doctors recommend HbA1C at least three times a year for patients on diabetic medication, coupled with lifestyle changes. This will help assess the treatment plan and check if the goals are met. Depending on the reference range, your doctor may change medication and dosage and recommend different lifestyle and dietary changes. Patients are advised to wait at least  6 weeks after making appropriate changes in medication, diet, and lifestyle changes to repeat the test.