Q: Every time my mother visits a doctor, she is advised to do the HbA1C test. Could you tell me more about the test?

This test shows a person’s average blood glucose level over the last 90-120 days. This can help the doctor assess your mother’s diabetes.

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Blood in our body contains different types of cells, including red blood cells (RBC). As blood travels through our body, the glucose present in the blood will stick to the red blood cells, or bind or glycosylate with the haemoglobin (the protein found inside the RBC). The more glucose in the blood, the more it will be found sticking to the haemoglobin.

Since the RBC lives about 120 days, an HbA1c test involves looking at mature red blood cells and seeing how much glucose is found sticking to them. The amount is measured in terms of percentage – an A1c result of 6 per cent means 6 per cent of the haemoglobin tested has glucose stuck to it.

There are some circumstances that can affect the accuracy of an HbA1c result – if you have had a recent blood transfusion, suffered significant blood loss, or suffer from some forms of anaemia.

The normal range of HbA1c level is about 4-6 per cent. This level compares to an average normal blood glucose level approximately 70-120 mg/dl.

The American Diabetes Association recommends people with diabetes keep their A1c levels below 7 per cent, which is a glucose reading of approximately 150 mg/dl on average over a 2-3 month period.

While an HbA1c check provides great information, it is not a replacement for daily blood glucose testing. Your daily tests should be reviewed alongside an HbA1c test to help you understand your daily and overall control. HbA1c only reports an average; it cannot show daily fluctuations. Conversely, you may need to do glucose checks at different times of the day. Always checking at the same times of day will limit your ability to fully understand your glucose levels over a 24-hour period. Because HbA1c is an average, it will not show if you are having problems with hypoglycaemia (low sugar levels) or experiencing unstable readings. It is an important test, but trends in your daily blood glucose cannot be identified by HbA1c results alone.

It is ideal to do HbA1c every three months, if your therapy has changed, or you’re not meeting treatment goals.

The term estimated average glucose, or eAG for short, is a new way of showing average blood glucose information in the same units (mg/dl) that people are used to seeing on their glucometers and glucose lab reports, rather than using percentage like HbA1c.

HbA1c percentage is sometimes confusing to people, so having your results in terms of a meter value may make the information more realistic. Still, it’s simply a different way of showing the same thing – your average glucose over a period of months. eAG is not exactly as HbA1c, but it is another way to interpret your control. 

Dr Asok Cheriyan is specialist diabetologist and general practitioner at Al Waha Clinic, Dubai. Got a problem? Our fantastic panel of renowned experts is available to answer all your questions related to fashion, well-being, nutrition, finance and hypnotherapy. Email your queries to friday@gulfnews.com.