Hb A1c test
What is Hb A1c Test?
This test measures glycated hemoglobin or hemoglobin that has blood glucose attached to it.
It helps to detect the levels of blood glucose over the past one to three months. Normally red blood cells have a life period of about three to four months. Blood sugar routinely binds with hemoglobin in red blood cells. The more blood sugar in the blood stream, the higher will be the percentage of glycated hemoglobin. Thus, this gives a better picture of diabetes management over a given period of time.
Why is it conducted?
The Hb A1c test can be used as a diagnostic tool as well as for examining control of blood sugar over the last few weeks. It is a more reliable test as compared to home testing records maintained by patients.
It provides an average level whereas fasting blood sugar tests sugar levels at testing time. It has been seen that people with lower glycated hemoglobin results have less probability of developing later complications of diabetes like heart disease, kidney failure, and retinopathy. It helps to gauge the trend of blood sugar control. This in turn helps to keep the havoc caused by both Type 1 diabetes and Type 2 diabetes to the minimum.
Who should go for it?
This test is primarily for diabetics and better management of blood sugar levels.
- Earlier, it was more commonly used for monitoring of diabetes rather than initial diagnosis.
- However, it is now also used for diagnosis purposes in people with a high risk of developing diabetes.
- People who have well-controlled diabetes are recommended to have this test done every six months.
- People with poorly controlled diabetes may have the Hb A1c test every three months.
- It is also carried out to check the efficacy of any change in diabetes medication.
This is a simple blood test that does not require any special precautions like fasting beforehand. It can be carried out at any time of the day. This makes it more convenient than other blood sugar tests, though it cannot take the place of daily monitoring required to adjust insulin doses for people with fluctuating blood sugar levels. The blood will be drawn from a vein in your arm.
Interpretation of results
The HbA1c test does have some limitations. Certain conditions affect the outcome of the test such as anemia and other blood problems, blood loss, blood transfusion, high cholesterol, diseased kidneys or liver disease.
Besides this, if you are taking vitamin C and E supplements, alcohol or steroids that raise blood sugar, the results are going to be affected. In the case of there being rapid fluctuations in blood sugar levels, this test may again produce unreliable results. If any changes have been introduced in treatment regimen for diabetes, it is better to have the next Hb A1c test after at least six weeks. This test is not considered to be suitable for assessing children and pregnant women.
An Hb A1c test result of:
- Less than 5.6 % indicates no diabetes
- Between 5.7 % to 6.4 % is an indication of prediabetes and needs to be watched closely
- Higher than 6.5 % is indicative of diabetes
- Results higher than 8 % indicate poor control of diabetes
The general target for people with diabetes is for the glycated hemoglobin to remain less than 7 % if they are to avoid long term health repercussions.
Written by: Nandita tripati
Date last updated: January 09, 2015