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What is glycosylated haemoglobin?
A small percentage of haemoglobin (the pigment in red blood cells) binds to glucose resulting in glycosylated haemoglobin in the blood. This binding remains for the rest of the life of the red blood cell, which is nearly 3-4 months. The level of the glycosylated haemoglobin depends on the long-term level of glucose present in the blood and its duration. It is used for monitoring the treatment in diabetics, and is recommended to be done at least twice a year.
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Why is the test done?
It is a good measure of diabetic control and poorly controlled diabetics have high levels of glycosylated haemoglobin. This test indirectly indicates the blood sugar levels of the previous 3-4 months.
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How is it done?
Blood is taken by venepuncture (from a vein) and sent to the laboratory where it is tested by haemoglobin electrophoresis (separation of different types of haemoglobin over a gel) or column chromatography (separation of different types of haemoglobin over a column). It can be measured at anytime and does not require a fasting or a post-prandial (after meals) state.
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What are the normal values?
4 – 6 % of total haemoglobin
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What are the abnormal values?
6 - 8% indicates adequate diabetic control
8 – 10% indicates that diabetic control needs attention
>10% indicates very poor diabetic control
