HbA1c Test to be Used for Diagnosis

When you were diagnosed with diabetes (or prediabetes), did your doctor do a fingerstick blood test in his office, or give you a fasting plasma glucose test? Or did he make the diagnosis based on your HbA1c level? Although some doctors are already using HbA1c test results as a diagnostic tool, you may be surprised to know that there are currently no official guidelines for doing so. However, that may be about to change.


The HbA1c test — a measure of blood glucose levels over 2–3 months that is usually used to assess how well a person is managing his diabetes — may soon be used officially to diagnose Type 2 diabetes as well. Earlier this month, the American Diabetes Association announced that a group of several leading diabetes organizations will publish guidelines in the next six months on using the HbA1c test as a diagnostic tool. Such a consensus statement is necessary because right now there is no agreement on what HbA1c level would constitute a diagnosis of diabetes.

Most people who don’t have diabetes have an HbA1c level of 6% or less, and those with a higher HbA1c level may have diabetes. In the future, the HbA1c test will probably be used along with other tests to make a diagnosis.

The tests currently in use for diagnosis are the fasting plasma glucose test and the less common oral glucose tolerance test. However, these tests can be inaccurate if a person has eaten recently or is sick. Advantages of the HbA1c test are that it can be given at any time and, because it reflects blood glucose levels over a longer period, it is not unduly influenced by events on the day of the test.

Do you think that using HbA1c as a diagnostic tool is a smart move? Do you remember what your HbA1c was when you were diagnosed? Let us know with a comment here.

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  • Gail

    At diagnosis 10.4
    3 mo later 6.5
    Over the many months it moved down to 5.5 and has been slowly creeping back up so that 2 mo ago it was 6.4 w/ workouts 25 out of the 30 days in Dec, meds as ordered, and dietary control.
    Next month I expect it to be up over 6.5 and MD plans to add Actos
    Now testing 2-3 times daily to find out what is going on in between. I know it is slow in returning to normal after a meal

  • Erik

    Sure I think it can and should be used, however since a quick fingerstick bloodtest gives direct results I think they should use both…

  • Erik

    Sure I think it can and should be used, however since a quick fingerstick bloodtest gives direct results I think they should use both…

  • Tony G

    I do believe the HbA1c test is a good diagnostic tool for diabetes. This is what the doctor at the Mayo Clinic used when I had a physical there recently.

  • Joan

    I think using the HbA1c as a diagnostic tool is a smart move since it shows glucose levels over a long period of time. This should help avoid decisions based on fingerstick or whole blood readings that can vary greatly.

  • Paula

    The HbA1c test shows how well your diabetes has been taken care of for the past 3 months. Why use the C-peptide test which identifies the function of the pancreas better by showing how much insulin is produced and whether it is a useful amount of insulin?

  • Ruth

    I think HbA1c would be very useful to DX diabetes as it gives a reading of the previous 2-3 months. As everyone who tests there glucose on a regular basis knows, the blood levels of glucose are extremely variable. Stress, nerves, exercise level, illness are a few of the things that may cause a variation of one’s glucose levels independent of what and how much you might have eaten.The HbA1c gives an average without the spikes and lows of the regular glucose levels.

  • psantana

    I think this is a good thing do to. My hba1c were almost 10 before i was diagnosed. I was eating good most of the time so the other test came back ok. I was just eating alot of white rice.

  • Edward

    When I was diagnosed with type II seven or eight years ago, it was from a HbA1c test as part of a yearly checkup. I’ve been under the impression that HbA1c was standard.

  • gailfreimann

    At Diagnosis: 7.1
    3 months later: 6.9
    1 year later: 6.1 to 6.2

    I thing the A1C is an excellent tool. In my case, my fasting blood glucose readings were in the caution area for a couple of years: over 100 but always below 110. Each time Dr. would say, “We need to keep an eye on this.” Had he checked my A1C, I’m sure it would have been plenty above 6.0 since at the 7.1 reading my fasting glucose was still only 106. I’m only glad another physician finally did check A1C and then order the GTT.

  • theresia

    What’s GTT?

  • luvariddle

    At Dx 8.9
    three months later 6.1
    three months more 6.1

    When BG was over 200, doc ran A1c, I never took an ‘official’ GTT, but he did do extensive BG tests and A1c every three months for monitoring.

    I think it’s an excellent idea, my BG changed dramatically in a year’s time, the A1c was a good indicator.

  • philsyes

    Diagnosed 11/15/07 – A1c 11.3
    By April 2008 – A1c 6.0
    In Sept 2008 – A1c 5.7

    I’m now on a 6 month schedule with my Doc since my BG is under control.

    My Doc suspected that I had “a problem” after treating me for my second severe skin infection (boil) within 2 months. He ordered a complete blood test it confirmed his suspicions. My serum glucose was 285.

    Now I treat the A1c test results as confirmation of my self test records.

  • jheidrick

    I think that the A1C test does a good job in finding out what you blood sugars have been for the last 2 or 3 months. I have had type 2 diabetis fot 35 years and my last A1C testwas 5.4.My doctor is considering changing my insulin to one of the newer fast acting insulin along with the Lantus.At the present time I use the R insulin before each meal anf the Lantus in the morning and before bedtime.I check my blood sugar before going to bed and is it is to high I take a small amount of the R before going to bed.

  • geriola

    I think it is inexcusable for any doctor to definitively diagnose Diabetes without having done a A1C. This measures over time. I understand that a finger stick in the doctor’s office can be indicative of a potential problem,but that is only a moment in time. Giving someone a diagnosis of Diabetes 2 changes one’s life forever. This happened to me and it was a very scary moment because no referral to a dietician, etc. was done. I was left to cope on my own. When an A1C was later done, my level was 6.0% and has remained so. I think pre-diabetic was better in my own particular case. That still means that I need to watch my diet and increase my exercise, but is not quite as scary as the diagnosis of Diabetes 2, without further information.

  • spuppymom

    My A1C at diagnose was 8.2. Now my Doctor takes it every 3 months and I maintain a 6.9.

  • bkasten

    I have been a Type 2 diabetic for over 12 years now and have seen the same doctor over that time period. Since day one, my doctor has always used the HbA1c test as the number 1 measurement for determining how I am doing and what medication he is going to prescribe to me.

    After reading your comments, I feel fortunate to have a doctor with his understanding of this terrible disease.

  • marcie

    Actually, while I agree that it can be helpful, I don’t think that it and a fingerstick should be the only criteria to diagnose type 2 in perhaps most cases.

    My husband’s A1c has never been above 6.0, but his fasting BG’s are often <126, and it’s not uncommon for his PP readings to be >180. And, he “flunked” the 2hrOGT. Sort of a mixed bag.

    When diagnosed, my BG (random) was >400, and my A1c was >10.0. No doubt there.

  • Paula Beaulieu

    I recently had my yearly physical and my blood glucose was 117. Prior blood tests showed blood glucose of 100 or less. My doctor ordered an A1c. I received the results today at 6.2. Doctor said it was slightly high. I don’t think I have diabetes. I do think that the test is an excellent tool and should be used in addition to the other tests for diabetes to help make the diagnosis.

    Posted by Paula June 15th 2009

  • nic

    HBA1C 8.0
    A1C molar 64

    wot do i need to do to reduce them

  • Diane Fennell

    Hello Nic,

    Thank you for your comment. For information about getting your blood glucose into target range, check out “Managing Your Blood Glucose Ups and Downs.”

    Diane Fennell
    Web Editor

  • Steve

    HBA1C on DX May 2009 10.3
    Put on 2 x 500 Metformin
    Today after following low carb diet and exercise,
    weight loss 56 pounds, HBA1C 5.1 and taken off meds!!. I believe that HBA1C is a critical indicator of diabetic health.

  • Jerry

    I was diagnosed with Type 2 Diabetes March of 2007. At the time, my A1C had never gone above 5.9. Since then my A1C is down to about 5.4 each time it is checked.

    My fasting reading though was very high when I was diagnosed (nearly 200). It had been high off and on for awhile. But it took my military doctor instead of my VA doctor to figure out that something was wrong. The VA only checked my A1C and they never figured out that something was wrong. I am so glad my military doctor paid attention to every test not just one.

    I am not sure, but my military doctor may have been suspicious when I had cellulitis twice in 2 months. If she did suspect something, she never said anything to me. I know that I was told that I couldn’t work until the second bout was completely gone which took almost 3 months. Shortly after I got over the second bout I was diagnosed with Type 2. So I’m not sure that the A1C would work for everyone.

  • Nigel Taylor

    I think it is a welcome move. If they are using the HBA1c as a diagnostic tool though it is imperative that the CBC be checked as low HB or high HB could elevate the levels of the A1c and lead to misdiagnosis. at the higher levels say 8 and above there is generally no controversy with use of the HB A1c but a multitude of factors do come into play at levels below this.

  • evelyn

    I’ve been taking galvusmet1000/50 within 2months. I went back to my doctor and my RBS is 131. the next I had my fasting Hba1c checked the result was 8.14., So, I think this is very high. My doctor said I should continue taking my medicine.May I ask you what should be the normal level of Hba1c?

  • Bridget

    I too ‘flunked’ the oral glucose test having first shown up in grey area of the fasting glucose blood test. Diagnosis terrible shock, especially since I was having a horrible time at work meantime and sobbed my way through the 2 hour wait in the GPs waiting room during the oral glucose tolerance test. (This is a test where you have to sit quietly for the duration, not allowed even to walk to sit in my own car, are not meant to be stressed, even the cold can skew the results.) Subsequently, 3 months later, my first HbA1c turned up at 4.9. Due for second HbAic next week and who knows? Have been sticking to a low carb diet (not as recommended by diabetes nurse and doctor – but I can’t see the sense of putting lots of sugars and starches into my body when it’s obviously having a problem metabolising carbohydrates) and have lost quite a bit of weight – could do better but this is not a race. So Diabetic or Pre-diabetic? Not sure. Being told I have the disease was one of the low points in my life. I was 51 and it was the first time I had to face up to the reality of an aging body. So, if the HBAic had been used as as a diagnostic test in my case, I don’t know whether my diabetes would have been confirmed.

  • ali

    my hba1c test is 7.4 what y advice me
    I take 2 tablets of metpaoral daily

  • Laurie Melisi

    I have been a diabetic for five years since the age of 46. When receiving the diagnosis I was doing all the right things. My weight was fine, I was exercising five days a week and eating properly. It was a huge surprise. In the five years after being diagnosed I was put on Januvia and 7 months ago on Lantus insulin at night. I was determined. So I exercised some more, went on Medi fast, lost 20 pounds and my numbers were perfect and my A1C was 5.1 during the last MD appt. He took me off all meds at that point that was 2 months ago. Now my numbers during the day are creeping up higher than they ever have been. Does anybody have a reason for this. I have also joined weight watchers as the doctor directed as he said Medifast was not a sustainable diet. I am at my lowest weight ever, 148. I made an appt for the MD at the end of the month. Had to go back on Januvia and still my numbers are high. Dont want to have to use Lantus again at bedtime. Any thoughts on why this is happening?

    • ucmass

      try to adjust timing. I eat all carbs between 8 am and 6 pm and my morning numbers are 116 or so, hba1c of 4.9. the timing can be an issue

  • Sandy

    Just received a test result of 6.1, does this mean I have type 2 diabetes?

  • Lita C. Malicdem

    My most recent doctor has been conducting a quarterly HbA1C test on me. I’m type II. I used to get results of 7% or a little more. I want to find out its implication over my self-management. My interest led me to Google. I’m grateful I did! I just found out, I’m in good control this last quarter with this result-6.5% (normal is 4.5-6.5%). I was a bit apprehensive then because my random BG count was over 8.94mmol/L on that same day he tested me. He assured me that it was just a “temporary occurrence” since I just celebrated my birthday with friends at home and in church. I’m glad to share my experience here as I’m benefiting likewise to this post including the comments. Thank you.

  • twyla

    I am a 67 year old woman and have pretty good health and still work and am vigorous. Had blood tests because my liver enzyme number was crawling up. I’m on statins for genetic high cholesterol. doc said to lay off wine for a month and see what happens. My AST number was at 122 so I didn’t have any alcohol for a month. Dropped to 57 so there is the answer. In the meantime, my doctors nurse said my HbAlc looks a little high at 6.58 so lets retest that at the same time we retest your AST. Came back at 6.79. I was in a real panic and then I ralized that I had been drinking a diet green tea, 0 calories drink in massive amounts because it satisfied me when others were having cocktails and I look at the label and saw that the second ingredient is honey. How can a drink have 0 calories with a second ingredient of honey and also sweetend with Splenda. I think I have discovered the culpret but will just drink water for a month and go back for another test and see what the results are. Have any of you ever had this happen and I am wondering if at 6.79 I am diabetic. Will talk to my doc next week.




    I have often feeling tired dizziness or fatigue sometimes after taking lunch meal one and half an hour passed. But I have checked my sugar test several times report is shown normal. What Can I do? My blood pressure is also often high 140/90 or 150/90-100. Please give me your suggestion.Thanks.

  • Wayne Padgett

    My HbA1c test my doctor said was 5.6 (normal) but yet my Glucose Post Fast was 101 over 98 even though the glucose level was high he told me it’s nothing to worry about because of my Hba1c test being normal and that it was more reliable. I have tingling loss of feeling in my big toes more on my left foot. I have red spots up and down both legs and he told me he believes that is due to dry skin and to start using lotion. I am still kinda worried. He told me if the loss of feeling gets worse to come back in and he will send me to a specialists for more tests. Was wondering if i could have nerve damage in my feet. I got this problem while working over night stock lifting and hauling heavy objects. However after reading this page and other online sources most say the Glucose Post Fast is more reliable so who do i believe and who do i trust at this point.