The hemoglobin A1c test tells you your average level of blood sugar over the past 2 to 3 months.
It’s also called also called HbA1c, glycated hemoglobin test, and glycohemoglobin.
People who have diabetes need this test regularly(2 to 4 times a year) to see if their levels are staying within range.
The A1c test is also used to diagnose diabetes (see HbA1c results indications below)
How the Test Works?
When glucose(blood sugar) builds up in your blood, it binds to the hemoglobin (a protein found in red blood cells. It gives blood its red color, and it’s job is to carry oxygen throughout your body) in your red blood cells. The A1c test measures how much glucose is bound.
Red blood cells live for about 3 months, so the test shows the average level of glucose in your blood for the past 3 months.
HbA1c results indications:
As an example, if your HbA1C result was 5 , then the estimated average of your blood sugar levels for the last three months was 97 mg/dL or 5.4 mmol/L based on the below formula.
The formula to get your estimated average glucose (eAG) is:
|eAG(mg/dL) = 28.7 × A1C − 46.7
eAG(mmol/l) = 1.59 × A1C − 2.59
Another example: if your HbA1c result was 5.4 then your estimated average glucose for the last 3 months was:
28.7 x 5.4 – 46.7 = 108.28 mg/dL
1.59 x 5.4 – 2.59 = 5.99 mmol/L