Significance of HbA1c in Diabetes

HbA1c provides a longer-term diabetes trend; average levels are over a period of 2-3 months.

Diabetes is a serious life-threatening disorder which is represented by increase in blood sugar levels. Increase in blood sugar level occurs due to reduced insulin production or inability of the body cells to react to insulin. In order to prevent diabetes related complication, it is important to keep the blood glucose levels in control.

Complications of diabetes can affect the entire body. Early diagnosis and appropriate treatment may help in preventing the onset of diabetes related complications. There are several investigations which help in the diagnosis of diabetes but HbA1c is the only investigation which gives indications regarding the control of blood glucose levels.


What is HbA1c?

HbA1c is an investigation which refers to the levels of glycated haemoglobin. Glycated haemoglobin develops when the haemoglobin joins with glucose in the blood. Build-up of glycated haemoglobin within the red blood cells shall highlight the average glucose level to which the cell has been exposed during its life cycle. More the average blood sugar more shall be the HbA1c levels.

When the blood glucose levels are reduced with medications, HbA1c levels too return to normal value. This investigation determines the average blood sugar levels in the previous few weeks/ months. This investigation is useful in screening and diagnosing diabetes and prediabetes.

HbA1c is an important investigation in diabetes as higher the levels of HbA1c, higher are the risk of developing diabetes related complications. Constant monitoring of HbA1c helps in reducing the complications caused by prolonged elevated blood sugar levels.

This test helps the diabetics to know if the medications, dietary restrictions and lifestyle modifications made by them to control diabetes are effective or not. It is an indicator to make adjustments if, blood sugar levels are not controlled. This test is advised once in 3 to 6 months, to assess if good control of blood glucose is being maintained.

HbA1c is also known as haemoglobin A1c or just A1c; Glycated haemoglobin test; Haemoglobin glycosylated test; Glycosylated haemoglobin test; Glycohaemoglobin test.


HbA1c as a Diagnostic Test in Diabetes

Apart from monitoring blood sugar control in patients with diabetes, HbA1c can also be useful as a diagnostic test in diabetes. There are certain conditions where HbA1c cannot be used as an appropriate test in diagnosis of diabetes, they are:

  • Children & young people.
  • Pregnancy.
  • Patients with diabetes for less than two month duration.
  • Suspected type 1 diabetes patients.
  • Patients on medications causing rapid glucose rise.
  • In acute pancreatic damage patients.
  • Presence of factors that influence HbA1c measurement such as altered haemoglobin, destruction of erythrocyte, erythropoiesis, glycation, hypertriglyceridaemia, haemoglobinopathies, hyperbilirubinaemia, chronic opiate use, etc.


How is HbA1c measured?

A blood sample is required to measure HbA1c. Blood sample is either derived from the vein or from the finger prick. The best part is that for this investigation there is no need of a fasting blood sample, nor are there any special preparations required for the test. Fasting blood sample is not required as the food that is consumed recently fails to produce any impact on the A1c test.


What Are the Limitations of Measuring HbA1c?

Levels of HbA1c cannot be used for adjusting doses of insulin as HbA1c fails to produce any impact of daily fluctuations of blood glucose concentration. This test is not helpful in determining the daily presence or absence of hypoglycaemia or hyperglycaemia.


Readings of HbA1c

  • If the HbA1c level is less than 5.7% of total haemoglobin then, it indicates a healthy level.
  • Level of 5.7% to 6.4% indicates increased risk of diabetes (presence of prediabetes).
  • Level of 6.5% or higher signals the presence of diabetes.
  • Levels above 7% in a diabetic person, indicates that the blood sugar is not well controlled.
  • Complications of diabetes can be delayed or prevented if the levels are kept below 7%

It is advisable to keep the HbA1c level less than 6%. The goal for people suffering with type 1 and type 2 diabetes is to keep the HbA1c levels below 7%, as levels below 7% have shown to postpone the complications of diabetes.

Results of HbA1c may be unreliable in people suffering with anaemia, certain blood disorders, liver disorder, high cholesterol levels or kidney diseases. If your HbA1c levels are higher, you need to make changes in your treatment plan along with the consultation of your physician, to manage your blood sugar effectively.


How to Lower HbA1c Levels?

To lower HbA1c levels, you shall have to control your blood sugar levels which can be achieved by following the below mentioned steps:

  • Dietary restrictions.
  • Lifestyle modifications
  • Physical activity
  • Medications or insulin, as per the requirement.


How does HbA1c test differ from a blood glucose test?

  • HbA1c levels indicate the average blood sugar levels in the previous few months while, the blood sugar level is the glucose concentration in the blood at a single point of time.
  • In HbA1c, fasting blood sugar sample is not required whereas in fasting plasma sugar test, it is necessary to provide a 10-12 hour fasting sample.
  • In both the test, blood sample can be drawn either, from the vein or from the finger prick.

Aashish Nanda



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