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What is HbA1c test? Is it a test for measuring blood glucose level for diagnosis of diabetes?

Date: 17 Dec 2015    Group: Doctors    Category: General Medicine   

Diabetes is diagnosed by measuring blood sugar level. Generally plasma glucose level is measured by taking fasting blood samples and postprandial blood samples. What is HbA1c test? Is it a test for measuring blood glucose level for diagnosis of diabetes? Awaiting responses from experts.

Searching for information about HbA1c test? Wondering what tests it? Find responses from experts on this page.

Author: Kiran    19 Dec 2015      Member Level: Gold     Points : 2  (Rs 2)    Voting Score: 0

HbA1c test also referred as A1c test, Hemoglobin A1c test or glycated hemoglobin test. When haemoglobin combines with sugar molecules, it is called glycated haemoglobin.

This test is carried out to diagnose diabetes by measuring glycated haemoglobin which indicates the average level of blood glucose over a period. Higher blood glucose level means higher HbA1c value and it indicates an individual at higher risk of diabetes.

HbA1c test provides average blood glucose level over longer period whereas blood glucose level measurement only provides the level of glucose in blood at the time of testing. HbA1c value is measured in mmol/mol and blood glucose level is measured in mmol/l.

Author: Venkiteswaran.    20 Dec 2015      Member Level: Diamond     Points : 6  (Rs 6)    Voting Score: 0

The two spot tests for diabetes diagnosis are Fasting blood sugar level test and the Post Prandial (after meals) blood sugar level test.
However these two give the status of sugar level at that point of time only. As the sugar levels are not uniform at all time, and vary at different times, different days, based on one's food, activity and medication. Hence to know whether a diabetic person is properly responding to the medication or life style adjustments as per medical advice and is having his sugar level under control within a range , needs another test which may give larger overall picture.
It is here that the Hb1Actest comes to picture.

Blood has a red protein called haemoglobin,( abbreviation used is Hb). Out of the few types of Hb the predominant variety which constitutes about 95 to 98% is the A1c type. The glucose in blood gets attached to this Hb and remains there for almost the life of the blood cells say about 3 to 4 months. (or called glycosylated heamoglobin).They slowly get cleared from the bloodstream gradually as a cycle by natural replacement. It is found that the amount of the Hb1Ac is indicative of the amount of glucose present in blood. However the the amount may be more in the cells of days near test and lesser in the older ones. Hence the average is taken of a three month period, which is more or less dependable. This test is thus called the HbA1c test.

Sometimes patients also do some tricks to deceive so that they may escape from the rigours of diet control etc. So before the fasting test or PP test, they observe ideal diet and activity so that results show very acceptable values. However the Hb1Ac will expose them and show what is the average level for the past 3 months.

So HbA1c is more a monitoring test to know the efficacy of medication and to know where the patient stands viz the sugar level control target. An ideal target for control in diabetics is the value 6 to 7 in HbA1ctest.

Author: buena    21 Dec 2015      Member Level: Bronze     Points : 4  (Rs 4)    Voting Score: 0

In simple words;
HbA1c is a test to measure the glycated hemoglobin in the blood.
Hemoglobin is a protein in the red blood cell which carries oxygen, when it combines with glucose it becomes glycated.
This glycated hemoglobin (HbA1c) amount in the blood is measured which gives an overall measure of the average blood sugar levels over a period of week or month.
Is HbA1c test accurate?
As the RBC's in the body survive for 8-12 weeks before renewal, this test which determines avg blood sugar level over a period of a week or a month gives accurate results.
This test is important for people with diabetes, as higher the HbA1c in the test greater are the risk of developing diabetes related complications.

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