Written by Tanya Thomas, B.Com | 
Medically Reviewed by Dr. Sunil Shroff, MBBS, MS, FRCS (UK), D. Urol (Lond) on Jul 27, 2020

Defining HbA1c

The HbA1c assay is the gold-standard measurement of chronic glycemia and measures the amount of glucose that binds to hemoglobin over a period of 3 months.

The HbA1c Test is often prescribed as a must-do blood test for pre-diabetic, type 1 diabetic or type 2 diabetic or even non-diabetics. So what exactly is HbA1c? How does this measure work? How will it help you manage your diabetes better? All this and more info on the HbA1c counter and teach yourself how best you can interpret your blood test results.(1)

HbA1c Blood Sugar Test

In the abbreviation HbA1c, Hb refers to hemoglobin while 'A1c' is a specific subtype of hemoglobin. Also called the Glycated/ Glycosylated Hemoglobin A Protein test, the HbA1c test gives the level of blood glucose estimated over a period of time (ideally 3 months or 8-10 weeks), The correct format of HbA1c is HbA1c but for convenience it is mentioned as HbA1c. Unlike the customary finger-prick blood test which reads blood glucose at a specific point in time, the HbA1c gives us a long range value. This reading of blood glucose is unaffected by immediate or short-term fluctuations in blood sugar and reflects how well glucose levels have been maintained over the specific period.

HbA1c test improves the effectiveness of diabetes treatment by tablets or insulin injection or both. It is a good guiding test by which the patient can understand how best he has controlled his condition and take further necessary corrective action.

The HbA1c test range should be as follows -

  • A non-diabetic should have an A1c result between 4% and 6%.
  • In Diabetics - A1c level should be 6.5% (47 mmol/mol) or higher.
  • In Pre-diabetes (increased risk of developing diabetes in the future): A1c is 5.7% to 6.4% (39 - 46 mmol/mol)

In most diabetic individuals the blood glucose level is higher and results in a higher HbA1c level. This higher level also reflects the possible level of damage to tissues due to glycation and hence diabetic complications. The normal recommended HbA1c readings for diabetics should fall within the reference range of 6.5 to 7%. What this really implies is that for every 100 red blood cells, 6-7 cells have glucose attached to them.

In the long term the importance of the HbA1c test can be understood from the fact that if well controlled, it lowers the possibility of vascular complications that can be traced back to diabetes.

Diabetes Control Chart

How often should one test with HbA1c

If someone is first diagnosed with diabetes or if the control of diabetes is not good then Hb A1c is usually ordered more frequently.

The American Diabetes Association recommends testing HbA1c at least twice a year.

Usually the test is conducted less often if diabetes is well controlled but most physicians would subject their patients to have the test 2 to 4 times each year.

When should HbA1c Not be Used as a test to detect Diabetes control-

Many epidemiological studies and clinical trials (UK Prospective Diabetes Study and the Diabetes Control and Complications Trial) have now established the importance of the relationship between HbA1c levels and risk for long-term diabetes complications. Today worldwide, HbA1c targets for diabetes management are used as the means to delay or prevent the development of complications.

"Medicine might Be winning the battle of glucose control, but is Losing the war against diabetes"

Diabetes Wallet Card

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  1. Is there a Relationship Between mean Blood Glucose and Glycated Hemoglobin? - (https://www.ncbi.nlm.nih.gov/pmc/articles/PMC3262729/)
  2. HbA1c: A Review of Analytical and Clinical Aspects - (https://www.ncbi.nlm.nih.gov/pmc/articles/PMC3819436/)
  3. Use of Glycated Haemoglobin (HbA1c) in the Diagnosis of Diabetes Mellitus - (https://www.who.int/diabetes/publications/report-hba1c_2011.pdf)
  4. HbA1c and Monitoring Glycaemia - (https://www.racgp.org.au/afp/2012/januaryfebruary/hba1c-and-monitoring-glycaemia/)
  5. Glycated Hemoglobin (HbA1c): Clinical Applications of a Mathematical Concept - (https://www.ncbi.nlm.nih.gov/pmc/articles/PMC5037982/)
  6. Significance of HbA1c Test in Diagnosis and Prognosis of Diabetic Patients - (https://www.ncbi.nlm.nih.gov/pmc/articles/PMC4933534/)

Latest Publications and Research on Decoding HbA1c Test for Blood Sugar

Do you wish to consult Diabetologist for your problem? Ask your question


amehra Friday, July 7, 2017

my HBa1c is 5.8% and fasting and pp sugar is less than 100. my insurance company rejects my term plan proposal only on this basis.Is it justified My all other tests including TMT,2D echo and all blood tests are normal

sharmalokesh79 Wednesday, May 3, 2017

my fasting glucose level 90, pp 139, hba1c range 8.2, i am not taking any medicine as of now, do i require medication

Ashish03 Thursday, July 9, 2015

Hi I have recently get my Blood sugar test and in Test result came is PPS [/hexokinase] 150 mg/dl 70-120. And GLYCOSYLATED Hb (HbA1c) 6.5 % 4.0-6.0. My question is does I have diabetes and what all precautions do I have to take to make it less and up to what point it should be less.

avinash1005 Wednesday, December 18, 2013

HbA1c Test can be a good measurement for diabetes, however genetic variations play important role in Diabetes. For example, genetic polymorphisms and mutations have been linked with Maturity onset of diabetes of young (MODY). There are about 15 genes associated with MODY, which were, till-date wrongly diagnosed as Type-1 diabetes. MODY donot require any medicines. Gene therapy and dietary changes alone can cure MODY diabetes. In patients diagnosed with type-2 diabetes, a genetic testing is recommended to find the best treatment for diabetes according to their genetic make-up. Certain dietary and life-style changes can even cure the disbetes completely in some individuals, but others may not be cured at-all from type-2 diabetes. Hence it is now recommended for comprehensive genetic testing for all patients with type-2 diabetes and MODY-type diabetes...

Gupta1952 Tuesday, December 17, 2013

There is big gap regarding declaring a person as Pre-Diabetic and Diabetic based on 1] Fasting and PP sugar levels 2) HbA1c levels. Many patients with with Fasting sugar less than 100 mg/dl and PP sugar less than 140 mg/dl show HbA1c level in the range of 6 % 0r 6.1 %. A person with Fasting sugar less than 100 mg/dl and PP sugar less than 140 mg/dl is considered Non Diabetic. On the other hand a person with HbA1c level between 5.7 % to 6.4 % is considered as Pre-diabetic. Two comments posted below on this website also confirm this discrepancy. For example Comment posted on 12/16/2013 [yesterday) showing Fasting and PP level as 109 and 139 ( only Pre-Diabetic range) but HbA1c as 9.4 which is very high and is severe Diabetic range. Similarly comment posted on 08/06/2012 stating that blood sugar fasting in last 6 months was 100 and 91 and pp as 122 and 102 Recently I did Hb1ac test and it gave 6.1. On the basis Fasting and PP levels the person would be non -Diabetic. in Reply just below that comment Dr Marks has declared the person as Pre-diabetic. SC Gupta

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