Time-in-Range v/s HbA1c

Dr Rajesh Javherani explains how continuous glucose monitoring presents a comprehensive view of blood sugar levels.

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Need for testing in Diabetes

As a child, I remember my grandfather checking his blood sugar levels by doing a urine test. It was a benedict solution, to which he would add a few drops of urine and would heat it. The change in the color would give him an approximate idea of his blood sugar levels. However, this process was arduous and erroneous.

From the urine dipsticks to capillary blood glucose sticks, blood sugar testing methods have evolved and metamorphosed. The silent nature of Diabetes makes testing very important. Testing helps the target values to be attained. Self-monitoring of blood glucose at home has become important in the life of a person with Diabetes. However, each reading only gives a stat value of blood sugar levels. The more frequent the sugars are checked, the better will be the understanding of sugar control.

Rise of HbA1c

Sometime in 1980's a test called HbA1c (glycosylated haemoglobin) was introduced which gave an estimate of average glucose value over a three-month period. The ideal target HbA1c value is 6.5 per cent, however it could vary according to the age of the patient.

Shortcoming

Imagine two people with similar HbA1c ranging between 6.5 to 7 per cent. However, person A has his glucometer sugar values close to 140-170 mg/dL and person B has sugar values ranging from 60 to 280 mg/dL with a history of hypoglycaemias or low blood sugar level. Both people have similar HbA1c, however, person B doesn't have good control of his blood sugar levels.

Continuous glucose monitoring