Decoding HbA1c Test for Blood Sugar

The HbA1c assay is the gold-standard measurement of chronic glycemia and measures the amount of glucose that binds to hemoglobin over a period of 3 months

The HbA1c Test is often prescribed as a must-do blood test for pre-diabetic, type 1 diabetic or type 2 diabetic or even non-diabetics. So what exactly is HbA1c? How does this measure work?  How will it help you manage your diabetes better? All this and more info on the HbA1c counter and teach yourself how best you can interpret your blood test results.

In the abbreviation “HbA1c”, ‘Hb’ refers to hemoglobin while ‘A1c is a specific subtype of hemoglobin.  Also called the Glycated/ Glycosylated Hemoglobin A Protein test, the HbA1c test gives the level of blood glucose estimated over a period of time (ideally 3 months or 8-10 weeks), The correct format of HbA1c. is HbA_1c   but for convenience it is mentioned as HbA1c. Unlike the customary finger-prick blood test which reads blood glucose at a specific point in time, the HbA1c gives us a long range value. This reading of blood glucose is unaffected by immediate or short-term fluctuations in blood sugar and reflects how well glucose levels have been maintained over the specific period.     

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HbA1c test improves the effectiveness of diabetes treatment by tablets or insulin injection or both. It is a good guiding test by which the patient can understand how best he has controlled his condition and take further necessary corrective action.

The HbA1c test range should be as follows -

• A non-diabetic should have an A1c result between 4% and 6%.

• In Diabetics - A1c level should be 6.5% (47 mmol/mol) or higher.

• In Pre-diabetes (increased risk of developing diabetes in the future): A1c is 5.7%  to  6.4%  (39 - 46 mmol/mol)

In most diabetic individuals the blood glucose level is higher and results in a higher HbA1c level. This higher level also reflects the possible level of damage to tissues due to glycation and hence diabetic complications.

The normal recommended HbA1c readings for diabetics should fall within the reference range of  6.5 to 7%. What this really implies is that for every 100 red blood cells, 6-7 cells have glucose attached to them.

In the long term the importance of the HbA1c test can be understood from the fact that if well controlled, it lowers the possibility of vascular complications that can be traced back to diabetes.


How often should one test with HbA1c

If someone is first diagnosed with diabetes or if the control of diabetes is not good then Hb A1c is usually ordered more frequently.

The American Diabetes Association recommends testing HbA1c  at least twice a year.

Usually the test is conducted less often if diabetes is well controlled but most physicians would subject their patients to have the test 2 to 4 times each year.  

When should HbA1c Not be Used as a test to detect Diabetes control-

• Pregnant women,

• Recent severe bleeding

• Recent blood transfusions,

• Chronic kidney disease

• Chronic liver disease

• Iron-deficiency anemia,

• Anemia due to Vitamin B12 deficiency

• Hemoglobin variants like sickle cell hemoglobin (hemoglobin S),.

Many epidemiological studies and clinical trials (UK Prospective Diabetes Study and the Diabetes Control and Complications Trial) have now established the importance of the the relationship between HbA1c levels and risk for long-term diabetes complications. Today worldwide, HbA1c targets for diabetes management are used as the means to delay or prevent the development of complications.

"Medicine might Be winning the battle of glucose control, but is Losing the war against diabetes"
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