Why hemoglobin A1c is not a reliable marker

104240029

Over the last few years doctors are increasingly relying on a test called hemoglobin A1c to screen for insulin resistance and diabetes. It’s more practical (and significantly cheaper) than post-meal glucose testing, and it’s less likely to be skewed by day-to-day changes than fasting blood glucose.

What is hemoglobin A1c?

Sugar has a tendency to stick to stuff. Anyone that has cooked with sugar can tell you that. In our bodies, sugar also sticks – especially to proteins. The theory behind the A1c test is that our red blood cells live an average of three months, so if we measure the amount of sugar stuck to these cells (which is what the hemoglobin A1c test does), it will give us an idea of how much sugar has been in the blood over the previous three months. The number reported in the A1c test result (i.e. 5.2) indicates the percentage of hemoglobin that has become glycated (stuck to sugar).

Why is hemoglobin A1c unreliable?

While this sounds good in theory, the reality is not so black and white. The main problem is that there is actually a wide variation in how long red blood cells survive in different people. This study, for example, shows that red blood cells live longer than average at normal blood sugars. Researchers found that the lifetime of hemoglobin cells of diabetics turned over in as few as 81 days, while they lived as long as 146 days in non-diabetics.

This proves that the assumption that everyone’s red blood cells live for three months is false, and that hemoglobin A1c can’t be relied upon as a blood sugar marker. In a person with normal blood sugar, hemoglobin will be around for a lot longer, which means it will accumulate more sugar. This will drive up the A1c test result – but it doesn’t mean that person had too much sugar in their blood. It just means their hemoglobin lived longer and thus accumulated more sugar. The result is that people with normal blood sugar often test with unexpectedly high A1c levels.

This confused me early in my practice. I was testing blood sugar in three different ways for all new patients: fasting blood glucose, post-meal blood sugar (with a glucometer) and A1c. And I was surprised to see people with completely normal fasting and post-meal blood sugars, and A1c levels of >5.4%.

In fact this is not abnormal, when we understand that people with normal blood sugar often have longer-lived red blood cells – which gives those cells time to accumulate more sugar.

On the other hand, if someone is diabetic, their red blood cells live shorter lives than non-diabetics. This means diabetics and those with high blood sugar will test with falsely low A1c levels. And we already know that fasting blood glucose is the least sensitive marker for predicting future diabetes and heart disease. This is a serious problem, because fasting blood glucose and hemoglobin A1c are almost always the only tests doctors run to screen for diabetes and blood sugar issues.

Another condition that affects hemoglobin A1c levels is anemia. People who are anemic have short-lived red blood cells, so like diabetics, they will test with falsely low A1c levels. In my practice, about 30-40% of my patients have some degree of anemia, so this is not an uncommon problem.

What blood sugar markers are reliable?

Testing accurately for blood sugar is like putting pieces of a puzzle together. Fasting blood glucose, A1c and post-meal blood sugar are all pieces of the puzzle. But post-meal blood glucose testing is by far the most reliable and accurate way to determine what’s happening with blood sugar, and the most sensitive way of predicting future diabetic complications and heart disease.

For more on why post-meal blood sugar is a superior marker, read my article When Your Normal Blood Sugar Isn’t Normal (Part 2). To learn how to test your post-meal blood sugars at home, and what healthy targets should be, read my article How to Prevent Diabetes and Heart Disease for $16.

Another useful – but underused – blood sugar marker is fructosamine. Fructosamine is a compound that results from a reaction between fructose and ammonia or an amine. Like A1c, it’s a measure of average blood sugar concentrations. But instead of measuring the previous 12 weeks like A1c, fructosamine measures the previous 2-3 weeks. And unlike A1c, fructosamine is not affected by the varying length of red blood cell lifespans in different individuals. Fructosamine is especially useful in people who are anemic, or during pregnancy, when hormonal changes cause greater short-term fluctuations in blood glucose levels.

To put the most accurate picture together, I like to have all four: fasting blood glucose, A1c, post-meal glucose and fructosamine. But if I only had to choose one, it would definitely be post-meal glucose.

Like what you’ve read? Sign up for FREE updates delivered to your inbox.

  • I hate spam too. Your email is safe with me.

Comments Join the Conversation

  1. SHAKEEL AHMED says

    Hello sir, My daughter age 1 y 5 m having problem of lesser HB 6.2 due to Due to Heart beat max 75. kindly advice prefer foods for raising her HB level.

  2. Matthew says

    I’m 41 yo, 6′ 3″ and 205lbs. About 6 months ago I started having LUQ pain, diarrhea, and some kind of like systemic neuritis. My GI doc tested my exocrine pancreas enzymes at super low and put me on an enzyme replacement. The nerve pain continued though, so my primary doc checked my A1c and found it to be 5.4. When I compared it to a previous result 6 months earlier and 3 others going back 5 years they were all 4.5 or below. I am scheduled to have it checked again soon but my question is whether a jump of .9% within the “normal range” is a significant number, or does it not matter until it reaches minimum unhealthy threshold?
    I have researched this since July and can find no information about how to judge A1c movement in non-diabetics. I have gone to a basically paleo diet for fear that a jump of that much, combined with my apparent PEI, means something not great is going on with my pancreas and that diabetes is inevitable. Maybe I’m wrong though and someone can educate me. My neuritis remains unabated, though my doctor assures me that at my current levels, it’s not related to blood sugar.

    • Catherine Nichols Pogorzelski says

      I came upon your query in searching for info on A1C, for my husband. But I want to reply to you regarding the “enzyme treatment” you mention above , if you have been given the RX drug “CREON” make sure to note there is a side effect noted on their website (ID taken this for 8 years and have “Fibrosing Colonopathy!” http://www.creon.com

      I now take OTC enzymes, Essential Enzymes, available from Vitamin Shoppe. Have you had lipase amylase and protease checked again? For years I haas undiagnosed/untreated **LYME I have Sjogren’s induced pancreatitis, which will result in some diarrhea. Please get that checked via SSA-SSB test, I test NEG on that, which happens in about 40% of patients, but I am diagnosed with Sjogren’s because of the loss of teeth , pancreatitis dry eye and mouth and some salivary stones. I suffered though MANY MRI’sw/ contrast, for most part for undiagnosed Lyme and one for pancreatitis.

      **get checked thru Igenix in CA as Labcorp & Quest’s testing are kept intentionally high with criteria to avoid diagnosing and treating patients because they don’t want to reveal the amount of Lyme cases are really out there (TEN time stye national average!) http://www.cbsnews.com/news/cdc-lyme-disease-rates-10-times-higher-than-previously-reported/

      If your neuritis is not being relieved, is it possible that you have ever had any MRI’s with contrast in your health workups? I feel my retention of GADOLINIUM contrast has caused so many issues from fibrosis added into colon/bowel, pain, dermal fibrosis, yellowing in whites of eye, contractures of hands and feet, etc. IF you HAVE had MRI’s w/contrast get blood checked, your local doc can order these thru Mayo Medical Labs:

      http://www.mayomedicallaboratories.com

      Page upon which “G” catalog tests appear:

      http://www.mayomedicallaboratories.com/test-catalog/alphabetical/G

      Gadolinium, 24 Hour, Urine
      Gadolinium, Dermal, Tissue*
      Gadolinium, Random, Urine
      Gadolinium, Serum
      Gadolinium/Creatinine Ratio, Random, Urine
      Gadolinium, Dermal, Tissue, will need to be done if and when I test POSITIVE for GADOLINIUM In blood and/or urine.

      (next note is for your doc if they WON’T listen to you!)

      If you are REFUSING to order any lab studies, I would like to request that you sign a copy of this letter and place it in my medical chart. You will also receive a copy of this letter via registered mail.
      Mayo Medical Laboratories: Reference Laboratory services for hospitals worldwide
      http://www.mayomedicallaboratories.com

      AUNT MINNIE & GE & $5 Million verdict

      http://www.auntminnie.com/index.aspx?sec=prtf&sub=def&pag=dis&itemId=106037&printpage=true&fsec=sup&fsub=mri

      Study links Gadolinium MR contrast to brain abnormalities
      By Wayne Forrest, AuntMinnie.com staff writer

      http://www.ncbi.nlm.nih.gov/pubmed/24475844

      Radiology. 2014 Mar;270(3):834-41. doi: 10.1148/radiol.13131669. Epub 2013 Dec 7.
      High signal intensity in the dentate nucleus and globus pallidus on unenhanced T1-weighted MR images: relationship with increasing cumulative dose of a gadolinium-based contrast material.

      Kanda T1, Ishii K, Kawaguchi H, Kitajima K, Takenaka D.

      http://www.propublica.org/article/ge-failed-to-adequately-warn-about-dangers-of-its-mri-dye-jury-finds

      Omniscan
      Specter of MRI Disease Haunts General Electric
      GE Failed to Adequately Warn about Dangers of its MRI Dye, Jury Finds

      by Jeff Gerth
      ProPublica, March 22, 2013, 2:41 p.m.

      $5 Million Verdict In The First Gadolinium Injury Trial

      Tags: claims, Gadolinium Verdict, GE Healthcare, lawsuit, lawyer, litigation, Product Liability
      A federal jury in Ohio has awarded $5 million in the first case to go to trial in the multi district litigation involving patients who claim injury from the body scan contrast agent gadolinium. The jury found that GE Healthcare failed to provide adequate warnings of the health risk posed to those with impaired kidney function from Omniscan. As we have reported, the GE product is a gadolinium-based contrast dye used in MRIs and other imaging scans. The plaintiff in the case, Paul Decker, contracted a debilitating skin disease — nephrogenic systemic fibrosis (NSF) — as a result of being injected with Omniscan for a magnetic resonance angiogram in 2005. At the time, Decker was also undergoing dialysis for end-stage kidney disease.

      also ask docs to check you for the following: FMD & AS,
      FMD=FIbromuscular dysplasia and Ankylosing Spondylitis; after 20+ years of feeing mistakenly told I had “FIBROMYALGIA” I recently found out these within the last few months. http://en.wikipedia.org/wiki/Fibromuscular_dysplasia and
      http://en.wikipedia.org/wiki/Ankylosing_spondylitis

      PS there are a lot of variables w/A1C and serum glucose and continuous checking to make sense of what YOUR body is doing in relation to Diabetes. Just because you have neuritis/neuropathy in the States, doesn’t mean it’s CAUSED form Diabetes, there are OTHER causes to this condition PN(peripheral Neuropathy also being caused from FLUOROQUINOLONE antibiotics such as Cipro, Avelox and Levaquin,
      http://www.medscape.com/viewarticle/809520

      FDA Strengthens Neuropathy Warning for Fluoroquinolones

      Robert Lowes

      DisclosuresAug 15, 2013

      which you may have taken months to years ago and would NEVER think to associate with current conditions. How are your calves and Achilles tendons and rotator cuffs? and statins may cause damage to body as wellStatins:
      http://www.spacedoc.com and http://www.webmd.com/cholesterol-management/news/20130319/high-dose-statins-linked-to-acute-kidney-damage

      • Judy Weintraub says

        Catherine, thank you for all the info in your 11/10 comment. The gadolinium info is important. i worry about the many people who are exposed to it. i wonder if chelation therapy can help reduce its effects. i just stumbled on information about the recent findings that gadolinium persists in the body indefinitely, contrary to what has been previously believed. There is plenty of info on the web about it. I happened to need an MRI soon after i learned this and when i filled out the form before the procedure, there was a place to give consent to having contrast. It was explained that all of the contrast would be eliminated from the body within 24 hours in people with healthy kidneys, and to inform the technician of any kidney problems. i did not give the consent. i was asked about it and i said i was concerned about the recent findings of indefinite persistence in the body of people with normal kidney function.

        When the tumor they were looking for (a pancreatic insulinoma) was not found by the MRI, the radiologist’s report said something about the patient refusing the contrast and that more information might have been obtained if not for that.

        Regretfully, i had a CT scan soon after that which also didn’t locate the tumor, so that was a waste of radiation exposure for nothing.

        The tumor was found by endoscopic ultrasound (EUS). It was only 1cm in diameter which is common for insulinomas, and they are often not found by CT and MRI. If i had it to do again i would just have the EUS and avoid exposure to harmful radiation and contrast media.

        It was the effects of my insulinoma which brought me to this site. Before it had been diagnosed, and before i had ever heard of it, i knew i was having fasting hypoglycemia, infrequently but severe, waking up on the floor, unable to get up, no memory of how i got there, unable to move, unable to enunciate words, the symptoms resolved quickly when eating a small amount of complex carb (oatmeal, rye bread). These and other symptoms only happened on waking.

        I had a CBC blood test in late February which showed my fasting glucose was 32mg/dL That is extremely low, the bottom of the normal range is 65. But i was asymptomatic except for on 5 occasions over 8 months.

        I was referred to an endocrinologist. What an idiot. He spent at least an hour with me but he said my symptoms were probably caused by my liver and he did not see any thing endocrinological about them.

        i’ve had hepatitis C, asymptomatic, for decades, i have mildly elevated liver function tests. That’s why the endo said it must be the liver. Idiot. I went to a gastro doc who said there was no reason to think the liver was involved (duh) and he said he thought it was odd that no one had checked my insulin levels to rule out insulinoma. He ordered that test. My insulin was higher than my glucose which was below normal, and that was diagnostic of the insulinoma. Low glucose is the signal to the normal pancreas to stop putting out insulin. An insulinoma just keeps putting out insulin.

        The endocrinologist had done blood tests and that was the first and only time i ever had an A1c test. It was slightly below the normal range.

        The endocrinologist wrote on the copy of the blood test results he faxed me, “sugar is great!” and “See a liver doctor!” My nonfasting glucose was slightly below the bottom of the normal range. By then i was eating at least 5 times a day and had eaten three times before the bloodtest, including in the car on my way to the doctor. I had shown him my home meter results which showed morning glucose in the 20s and 30s, and going up during the day to a maximum of in the 50s or 60s. i showed him my 30 or so bloodtests going bad to the 80s, and showing that my glucose was always in the normal range in the 80s and 90s and until 2006, when it was low for the first time, and all the blood tests i had after that one were low, including one in 2010 that was 33ml/dL. That was the last one i had until 2014.

        Insulinomas are almost always benign and are 100% curable by surgical removal. but many people go years undiagnosed because it’s rare and doctors don’t think to test for it. But an endocrinologist?? i would think someone with that training would at least want to rule it out. But no. Fortunately, that was the first thing the gastro doctor i saw thought of. At least some people have a brain.

        After the insulinoma was removed, i had very high glucose. My normal pancreas islet cells had not had to function to lower glucose in apparently about 8 years, 2006, so they didn’t function initially. i was given insulin when i was in the hospital recovering, but i didn’t have to take any at home. My glucose continued to be usually above the normal range in the weeks after the surgery, but only in the low 100s, like 101 to 120, and over time, it continues to average lower. In the past couple of weeks it has been in the 80s and 90s with one result in the 70s, so it appears the pancreas is becoming normal again, hopefully. I’m only 13 weeks post op.

    • Elaine says

      Good morning,

      I am a 56 year old female who recently took a blood test. My doctor told me over the telephone that my blood test was good but I had one test for liver functions that was a bit high. He suggested for me to retake this test in a month. So I asked his office to send me my results via mail. I got it finally yesterday and noticed that my AC1 test was elevated 6.6 and my glucose test was within the normal range. Does that mean I have Diabete? Why didn’t my doctor tell me anything? Is he incompetent? If I didn’t ask for my copy if the test I wouldn’t even have known about it. What should I do now!
      Thank you for any advise.
      Elaine

    • Elaine says

      Good morning,

      I am a 56 year old female who recently took a blood test. My doctor told me over the telephone that my blood test was good but I had one test for liver functions that was a bit high. He suggested for me to retake this test in a month. So I asked his office to send me my results via mail. I got it finally yesterday and noticed that my AC1 test was elevated 6.6 and my glucose test was within the normal range. Does that mean I have Diabetes? Why didn’t my doctor tell me anything? Is he incompetent? If I didn’t ask for my copy if the test I wouldn’t even have known about it. What should I do now!
      Thank you for any advise.
      Elaine

  3. Bill Kwolek says

    My A1C is down to 6.1. Is there a normal level? Do you ever reach a level where you can stop medication? I will ask my doctor at my next appointment. Just wondering out loud..

    • Mary says

      Bill,
      Most physicians expect diabetics to have complications. What do you want in your life? There are also some Youtube videos on this subject that might be useful.

      Dr. Richard Bernstein (an 80 year old Type 1) is one who says blood sugars should be lower than others advise in order to avoid the many complications of diabetes.
      My own A1C was 5.4 about a month ago. Dr. Bernstein feels that 5.6 is diabetic.
      Most labs seem to say that 7 is okay. At 7 your blood sugar is high enough where it may cause real damage.

  4. Lexi says

    Thank you Chris, for this article. I don’t know how I missed finding it until now. My A1c has been 5.8 – 5.9, but insulin as well as triglycerides are very low, and fasting bg normal. I had been concerned about the elevated A1c until now.
    Also thank you Kurt Harris for the helpful comments above.

  5. Ross says

    Can I pass the a1c test and still have diabetes? For 9 daysy feet and calves are cramping, I have pain in both feet, hands and legs, thirsty always, urinate constantly and I’ve list 25 ps in 6 months?????

    • Mary says

      It looks like an A1c of 7 is “passing” at most labs. Not sure what you are calling a passing level.

      That high a level is an invitation to complications.

    • Mary says

      P.S. I have read that the b-vitamin benfotiamine can assist with neuropathy symptoms. Check out iherb.com or swansonvitamins.com for some good prices.

  6. Jen says

    Hi Chris,

    I am a 41 year old female with a BMI of 18, no family history of diabetes, who leads a very active lifestyle, running about 20-25 miles per week. I have never been overweight. I recently had my HgA1c measured at 5.9, so I decided to start checking my blood glucose at home. All of my fasting measures are in the 80s. My accuchecks 2 hours after breakfast have been 80s-90s consistently. I have noticed that, depending on what I eat, my glucose 2 hours after lunch ranges from 100s to as high as 137. The numbers in the 130s seem to occur after I eat over 80 gm of carbs. When I keep the carbs to less than 50 gm per meal, I tend to stay below 120 2 hours after eating. I generally do not snack in between meals. What is your take on these numbers?

    Also, in my research, I ran across this article about a study of HgA1c performed on cyclists whereby HgA1c increased with increasing intensity of training. What are your thoughts on this? Do you think there may be some physiological adaptation with endurance training that causes HgA1c to be inaccurate in this population?

    Thanks for all of your helpful information!!

  7. Shea Hensley says

    Chris, I appreciate the articles. I am new to this, but my situation is a little different from others I’ve read/talked to. My A1C came back 8.3 – but my triglycerides are low in the normal range. Glucose at the time was at 177, but I was also tested in the late afternoon. I had been on warfarin for 7 months, but was taken off 2 weeks before my blood work was drawn. Have you heard of this before. I have been told by cardiologist, GP and other people and doctors that the correlation between A1C and Tri’s are both usually high.

  8. John says

    Good article. Doctor #1 said I was diabetic. Went to an endocrinologist #1 and he agreed. Put me on Metformin and later Glimepiride. Even had me take a 72 hour continuous glucose monitoring and showed high levels of glucose, but A1C usually ran deceptively low. Sticks and A1C did not correlate. No one could give me a reason why. Since A1C was normal, Dr. #1 said I don’t need meds anymore. I knew that was wrong because if I stopped the meds, glucose woule go back up. Dr. #2 said yes I do need meds. I didn’t go to medical school, but when my tests didn’t correlate, I knew at least one of the test had to be wrong, but neither doctor could explain why. Went to six hours of diabetes education classes at the hospital and the certified diabetes educators didn’t know why I was abnormal.

    Went to a second endocrinologist, doctor #3, and he immediately said I had a hemoglobinopathy. He kept me on the previous meds plus added Farxiga. Farxiga allows kidneys to pass sugar out through the urine instead of recycling the sugar. Now my fasting sticks have dropped by half to 120-135.

    I have to get fructosamine tests in the future to get a more accurate reading. A1C tests may be okay, but doctors need to realize its not the only test out there and certainly not 100% reliable for 100% of all patients. If different tests don’t match, ask questions until someone can answer them. Patients have to be in control of their own health care and not turn everything over to others. Doctors and the Internet are resources that can give patients information to manage their health.

    Checked a couple of diabetic websites and they didn’t even have the term hemoglobinopathy in their search engine. That’s scary and shows that there is a problem with diabetes education. Called one of the sites and never could get through. Got annoyed for ten minutes of being on hold while their messaging tape kept asking for donations.

    Glad you have this site and continue to pass the word.

  9. Cinzia says

    Hi Chris,
    I had my A1C a year ago and it was 4.9 which is a low but normal range. I have hypoglycemia. Should I get tested once or twice a year? Since I’m not diabetic, my bs levels are mostly at a low. By low I mean, there’s times I wake up with it at 62-75. Don’t feel good at those numbers. I do eat 5-6 small meals a day to keep my bs levels up. It can get erratic. It could drop to 73 after only 2 hours after eating! Don’t do any sugar whatsoever. When it’s in the 60’s or even 70’s, I’ll drink a little milk to bring it up. Was tested for insulinoma..do not have that. It’s just a constant battle to keep my bs levels at a normal range. My doctor said I’m doing everything right regarding my diet since food is my medicine, so there’s not much the doctors can do. I feel the best when my bs levels are in the 80’s and 90’s which will be at that range after I eat. I usually don’t eat anything after 6:00pm, so by the time I wake in the early am and I mean early, sometimes I think my bs levels wake me up, as I said, my levels could be in the 60’s or 70’s. Anyway..I’d appreciate any feedback you can give me. Also..I don’t overdo carbos, don’t eat white potatoes, white bread, any junk food. I eat protein at every meal, salad, veggies, cottage cheese, cheese, lowfat (2%) yogurt, milk, chicken, turkey, olive oil, flax seed, beans. As you can see, my diet is pretty good, but yet..my blood sugar can be so crazy!!! Thanks again for listening and any input that you feel could help me…

    • Cinzia says

      Hi Chris,
      I had my A1C a year ago and it was 4.9 which is a low but normal range. I have hypoglycemia. Should I get tested once or twice a year? Since I’m not diabetic, my bs levels are mostly at a low. By low I mean, there’s times I wake up with it at 62-75. Don’t feel good at those numbers. I do eat 5-6 small meals a day to keep my bs levels up. It can get erratic. It could drop to 73 after only 2 hours after eating! Don’t do any sugar whatsoever. When it’s in the 60’s or even 70’s, I’ll drink a little milk to bring it up. Was tested for insulinoma..do not have that. It’s just a constant battle to keep my bs levels at a normal range. My doctor said I’m doing everything right regarding my diet since food is my medicine, so there’s not much the doctors can do. I feel the best when my bs levels are in the 80’s and 90’s which will be at that range after I eat. I usually don’t eat anything after 6:00pm, so by the time I wake in the early am and I mean early, sometimes I think my bs levels wake me up, as I said, my levels could be in the 60’s or 70’s. Anyway..I’d appreciate any feedback you can give me. Also..I don’t overdo carbos, don’t eat white potatoes, white bread, any junk food. I eat protein at every meal, salad, veggies, cottage cheese, cheese, lowfat (2%) yogurt, milk, chicken, turkey, olive oil, flax seed, beans. As you can see, my diet is pretty good, but yet..my blood sugar can be so crazy!!! Thanks again for listening and any input that you feel could help me…also I wanted to add..I take 50mcg. of Synthyroid daily for my low thyroid, I’m 118-120 lbs which is perfect for my 5’5″ height and my BMI is 19

    • Dave says

      Cinzia, I was surprised I finally found correspondence from another hypoglycemic person. I have suffered from it as far back as I can remember, maybe 8 years old. My sister and I would both call it “that far-away feeling”, since that’s how we would feel. It wasn’t until my sister became a nurse and suffered an episode. She had her blood sugar tested and it was 50! She then told me it was hypoglycemia. I am now 58 and was recently in a motorcycle accident. The nurse came in and asked me how I felt. I said fine, except for the road rash. She said “Really? Your blood glucose is 60.” I told her yes I have hypoglycemia and I don’t usually feel it until it gets very low. I have found that eating five or six small meals a day helps more than anything. Drinking coffee early in the morning can cause an attack. Not eating breakfast can cause an attack. I usually get it if I don’t eat much for breakfast, drink coffee and take a brisk walk. When I stop walking, it comes on… Since I’ve had it 50 years, I guess there’s not much to worry about.

  10. sharon says

    AIC. Anyhow have (other than me) a LOW retic count? Any doctor check that? I have a very very low retic count and wonder how that affects my a1c reliability. Thank you.

  11. Ken says

    While diabetics do have shorter lived red blood cells, and that does matter, when comparing diabetic A1Cs, you are being compared to other diabetics generally, not the normal non diabetic population. So this does give you a good idea of how you stack up to other diabetics, as well as monitoring your own progress by comparing your own readings over time. So in other words, the targets for good control are diabetic ones which take this into account as do the studies that produce these targets.

    So there are indeed two different references here, longer and shorter lived, diabetic A1C targets are higher but that’s pretty much by design.

  12. judy says

    i was recently tested for Hemoglobin A1c because i presented to an endocrinologist with extremely low blood glucose on lab test and some scary symptoms, not the ordinary hypoglycemia symptoms. My A1c was 4.7 which registered as low (L) on the lab print out–it was only slightly low. Does a low score on this suggest a possibility of short-lived RBCs? Does it have any relationship with extremely low blood glucose? my result at the lab, fasting, was 32mg/dL.

    Not long after that i got a home glucometer and i get the same kind of results on that as the lab got, in the 20s and 30s first thing in the morning, every day.

    did not know i had hypoglycemia until i had that lab test, though i had had one episode where i woke up with ataxia, i fell while walking to the bathroom first thing in the morning, i got up and immediately fell again. I soon found that i had very impaired coordination. i did not know why and i was very worried. Eventually i wanted to have breakfast but had great difficulty holding the measuring cup under the faucet, to get some water to heat, to make instant oatmeal, i lacked the coordination to get the water into the cup. I persisted and did make the instant oatmeal (pour hot water onto flakes and it’s done), and i got my lap top and was eating the oatmeal and i suddenly was aware that the symptoms were going away. Previously i had been unable to type. While eating the small amount of oatmeal, i realized i could type. That was about a month before the lab test.

    Since it only happened that once, i put it out of my mind. About 5 days after the lab test, i had the second episode, worse than the first, i woke falling out of bed to the floor, couldn’t use my arm to break the fall, i didn’t have the coordination. i sat on the floor, i could not get up and walk, I crawled to the kitchen and began eating a piece of whole grain rye bread, sitting on the floor, and before i had finished one bite, i felt the symptoms go away and i knew i could get up and walk.

    So since that day, i have thought of myself as ‘hypoglycemic.’ I look pale, i feel groggy, i am in poor shape. I have had some blood tests, a non fasting repeat of blood glucose was 63 (after eating three meals in the previous 4 hours), i had the A1c scoring 4.7. More recently i’ve had another lab test which included non fasting glucose and insulin. Glucose was 53 (i had eaten about an hour before the test, whole grain rye bread, tuna, apple), insulin was 58, which is high.

    I was wondering about the A1c and after reading this article, am wondering if this could be evidence that my RBCs are short-lived. I have no results showing anemia, most recent result in late Februarly, was 4.60 and previous tests didn’t show low RBCs. Other CBC results were normal.

    After realizing i was hypoglycemic, i started eating frequent meals and i started feeling better and my head got clearer, but then after a couple of months, i was slacking off on the number of meals and i was going back to my previous habit of not eating breakfast when first arising but going for a 1/2 hour walk, doing some yoga, maybe straightening up the house. I began feeling less well and my glucose results on my home meter were getting lower and lower.

    Two weeks ago, i woke up one morning laying on my back on the floor by the foot of my bed, having no idea how i got there. i couldn’t move, i couldn’t get up, until about 10 minutes went by and then i could sit up. i saw that i had knocked over my valuable guitar which was laying on its face on the floor, i have no memory of that.

    i crawled to the kitchen and ate a piece of rye bread, and was able to get up and walk, but not feeling too good. The next morning it was similar. I woke laying on the floor next to my bed, no idea how i got there, unable to get up, stuck on my back, struggling to get up, no results, for about 10 or 15 minutes, it was like being in a dream state, i did not understand what was going on, i had some weird thinking, like a dream, and then gradually i got to a normal state of consciousness and ate a protein bar which i had put in my room the night before just in case, and then i could walk to the kitchen and make breakfast.

    Since then, i’ve been eating very frequently and was also eating during the night and before getting out of bed in the morning.

    I have been using a home glucometer since early March, i always have really low glucose in the morning. Once in a while i get a result int he 40s and cheer because that is such a good result for me–the 40s is high for me in the morning, i hit about once every 2 or 3 weeks. When i started eating a lot, including during the night, the results on the meter began increasing, the 7 day average was in the 60s. But then, i stopped eating during the night, it seems very unhealthy to me, i hate doing it and can’t sleep, and i don’t know if that is why but my numbers have been going down.

    The doctor who saw me on Monday and referred me to another endocrinologist described me as pale and fatigued (he was recording his comments, like chart notes). I saw my Chinese doctor yesterday and she looked very worried about me, she said i was pale and she emailed me this morning and asked how i was and told me she wanted me to come in for a treatment.

    The GI doctor that the first endocrinologist sent me to said he thought it was odd that no one had taken insulin levels and said that insulinoma should be ruled out based on the history. So, he ordered blood tests that included glucose and insulin, he referred me to the second endocrinologist who i will see in 5 days, the earliest appointment i could get, despite reporting my symptoms. I want to know what testing i should ask for to help diagnose what is going on.

  13. sharon says

    I meant to check that I wish to have any follow up comments sent to me. I am early 50s and exhausted all the time. Thank you so much.

  14. sharon says

    Hello. You have been so helpful. My issue is that I have a very very low Retic count. But I do not have Anemia. I have searched for days to see if my Retic count could be giving me a falsely low A1C (which is 5.6) as my post prandials and fruct are very high and I am trying to make sense of it. Thanks!

  15. sarah says

    My question is I had an A1C check because I went to ER with low blood sugar but mine came back at 5.6. I was told I have reactive Hypoglycemia. I am on a strict diet of no more than 7g of sugar per meal and no more than 27g of carbs per day. I am totally confused on why my blood sugars will spike into the 300s but even after eating what I am supposed, an hour later, mine will drop to the lower 50s and I feel like crap. Also, the one hour checks after meals don’t work for me, and the doctor couldn’t explain what was happening because it went against “text book”. My sugars always spike about 5 to 10 minutes after i eat but drop to low levels after that hour mark, so it’s not an accurate reading. I failed my glucose test and can not take that anymore either…but how can i fail it, and told it’s hypoglycemia? Confused person over here…..

  16. Mary says

    For those wanting to take readings before and after meals, get a home blood glucose meter and test strips. The cost will be less than a doctor’s visit and take a lot less time.

    Walmart Relion Ultima has some of the lowest priced testing meters and strips and the strips are individually foil wrapped so not exposed to air every time you test.

    You can only use the type and brand of test strips that are specific to your meter.

  17. Kathryn says

    Anyone know anything about the concept of high glycators vs. low glycators? This is another variable in determining HbA1c levels that I think I read about somewhere.

  18. Giovanni Ciriani says

    My wife tested at 5.7% A1c which represents the lower bound for increased risk for diabetes. Given that her resting heart beat is much lower than the average population (50 or less BPM), would that increase the lifespan of RBC, and therefore increase the result of the test? She also had 12 radiation therapy sessions on one cervical vertebra for bone metastasis, and I was wondering if that also may change RBC turnover therefore affecting the result of the test.

  19. Bob Jennings says

    I am glad I found this article. I used to worry about my A1C all the time and believe the worry raised my blood sugars. After the latest article where the person say’s they can relax now and not be stressed was nice to read. I am 72 now and have regularly run high A1C’s mostly in the 8’s and also in the 9’s since I have been checked by this test yet I have no trouble with any diabetic problems. My eyes are fine and all my organs. So I never have been convinced the test is the God’s truth! I have been on insulin since 1995. I told my Doctor about this article but he dismissed it and said “You can’t believe everything you read on the computer”. Well as a living example of the way I respond to A1C tests I think I am! I am sure my blood cells are the rebellious type to this test by now. I am not worried at all about it anylonger!

  20. Cam says

    Thanks for helpful article, Chris.

    I’d like to add, however, that A1c results can be skewed both upwards and down by in response to differing kinds of anemia. With iron-deficiency anemia, for example, my understanding is that A1c results can be skewed misleadingly high.

    The A1c test is complex and controversial, as you have pointed out.

  21. Tiffany says

    Hi Chris,
    This is such an informative article. I would like to know the best time to check my post-meal glucose.

    Thank you.

  22. Teri says

    I was diagnosed in 1986 with gestational diabetes with my second pregnancy, and took insulin twice daily. As expected, after I had my daughter, my sugar levels were normal. But I was told to expect to go diabetic when I hit about 40. I had normal BG levels into my early 40’s. At 42, I was diagnosed with Hep C (much to my surprise), and did a 6-month ribavirin and interferon therapy. It wreaked havoc on my body, including my red blood cell count. Shortly after treatment commenced, my doctor called to tell me that he wanted to put me on metformin. I was taken off of it about 6 months later because he said that my a1c was normal. I was about 108 lbs at the time. I gained about 16 lbs about a year later, so I expected to be diabetic again. I asked to be tested, and again was told my a1c was normal. I tested myself with my glucometer, and had high fasting sugars, and high PB’s. I went back to my doctor and told him about my readings. He brushed it off, siting that the a1c is normal.

    It has now been 7 years since I was taken off metformin, and I KNOW I am diabetic It is in my family history; mother, grandmother, sister. I don’t know how to convince my doctor otherwise.

  23. Vivian says

    Hi There.

    I am 44 years old and female. 45 in May, 2014.

    I am 5 feet five and currently 202 lbs.

    I was 213 lbs in December 2013 but am losing weight following a semi Paleo diet. I am not eating grains, beans or added sugars.

    I take that back. I have had some agave, and organic peanut butter/chocolate with very low added natural sugar. I do eat fruit.

    I still have some dairy. Not a lot. No ice cream or cheese.

    I have coffee everyday with organic cream. I have had plain, whole fat organic yogurt.

    I have been doing this for nearly a month now.

    Before I started my AIC was 6.3 and my fasting blood sugar was 102. (January 2014)

    My primary care physician and endocrinologist said I was pre diabetic but not diabetic.

    I didn’t have any blood sugar issues until I was 42.

    (As far as I know.) Last time I was checked I think I was 34 or 35.

    In my late 30’s (36-38) I exercised a lot and ran races and 2 full marathons. I didn’t really watch what I ate per se but my weight was around 170. Still overweight but physically spry.

    Then between 38-42 all that went by the wayside.

    My weight went over 200 lbs and I just ate whatever.

    Then I lost 40 lbs at 42 yrs of age but then gained it all back.

    It was at 42 I found out my blood sugar was 102 fasting. It had (as far as I know) never been over 100 before.

    While I was working out and watching what I ate in my early 40’s my fasting blood glucose came down to 94-96. My AIC was 5.8 – 5.9.

    I have always struggled with weight since I was a teen. I was diagnosed with PCOS at the age of 29.

    I am a sugar addict big time. Intellectually, I KNOW what to eat.

    I know when I am eating junk I know how dreadful it is health wise.

    I do have high cholesterol and Triglycerides.

    It was 311. LDL over 200.

    After 3 weeks of semi Paleo my AIC came down to 5.7. But my fasting glucose was 104.

    My cholesterol came down to 295. LDL is still 205.

    (My blood was drawn February 10, 2014)

    Here’s the thing. How do I get a Fructosamine test done?

    My Endocrinologist said it was the same thing as AIC.

    I want to get a blood glucose test done as well.

    I have no clue what my post meal blood sugars are.

    How accurate would they be now since I am following a much healthier food plan?

    What would they have been when I was eating cake and ice cream?

    Maybe I was diabetic post meal and fructosamine wise but not AIC and fasting blood sugar wise three to 4 wks ago?

    I am confused and scared.

    Will a potato and rice post meal test be as accurate as a sugar drink test at the docs office?

    I don’t know if my Endo will perform a blood glucose post meal test?

    What do you do? Hang out at the docs office all day?

    Ok thank you!

    I know this is long!

    Best,

    Vivian

  24. Norm says

    I have been on metformin ( 4- 500mg/day) for 1 year. My fasting BG is between 95-106. 1 hour after meal its 125-130. My A1c was 6.9 3 months ago and recently it rose to 7.4.
    My triglycerides are 120; LDL 90, HDL 45.
    Not sure what changed. I have lost 10 lbs since last year as well. Any suggestions as to what I can do to lower my BG and A1c?

  25. Elaine Puricelli says

    What about people like myself?
    My A1C number didn’t change much at
    all after my distal pancreatectomy.
    But aren’t I now at a bigger risk of
    developing diabetes post-operatively,
    in the here and now since I can’t replace
    the pancreatic tail?

  26. Ken Orland says

    Chris,
    Just had a checkup and my fasting glucose was 110, last year it was 120. Both years my a1c was well within normal levels. My dr wants me to diet and exercise and recheck blood in 3 months. I am a very anxious person and the dr feels this can raise the fasting glucose. What would you suggest?

  27. Mary Katherine says

    From what I’ve read the studies on anemia are conflicting. It’s been found that anemia raises a1c, lowers a1c, and has no effect on it. Here is information from a study in India (reported 2 years ago) that said anemia falsely lowered a1c. However they said prior results were conflicting so they did their own study, and the conclusions were not supported elsewhere. They said further study is needed.

    I don’t know anything about other research, but they differentiated between mild, moderate, and severe anemia. It appears that all of the patients had either moderate or severe anemia. I have mild anemia and it appears none of the patients had this. At any rate the doctor told me not to worry about it. I think just saying anemia may not be sufficient; also this study only considered iron-deficiency anemia.

    But I’m a diabetic with an a1c in the normal range without meds (5.4%) but it’s a good reminder not to get complacent and test blood sugar. b/c if I slack off things can go the wrong way. My hemoglobin is 11.3.

  28. Bob Jennings says

    My last A1C test was 9.5. When I check my blood sugars morning and evening they rarely go over 200 mostly around 150 and I am on 40 units am, 50 units pm before meals. Two shots per day. Many times I hit 120 to 125 or down to 65 if I get too low. Another diabetic says I will go on dialysis and loose my legs but I don’t believe that. I am 72 and still doing well. I have my doubts about this test. My body always has been in the 8+ A1C range. My doctor said to increase my morning shots. Well I did and had a very low blood sugar early afternoon. I just don’t see how why I strike that high on the AIC tests? My friend is severe diabetic and goes anywhere from 50 to 350 all the time yet he comes out with a 7 on his A1C. I seem to be much healthier than he is. This is why I looked up this article. I don’t think the A1C test is at all accurate.

  29. Cheryl says

    Dec. 2011 I had a complete physical. My A1C was 6.2. I lost 20 lbs. and cut out sweets and limited my carbs. I was retested three months later and my A1C was 6.1. I read that broccolli reduces glucose. Well, I have been eating broccolli for almost two years with dinner … close to everyday. I went to my doctor Oct. 2013 for retesting. My A1C results were 5.6 and I eat rice, pasta, and bread whenever I desire ( in moderation). I also started taking Bilberry capsules once a day for about
    three months now. It is my opinion “BROCCOLLI WORKS! “

  30. E Hamm says

    I have daily after meal readings of 200- 365 and fastings of 180-199 but my A1c is only 8.1 I am on oral meds but the more they increase the higher my daily sugars. I also have antiphospholipid syndrome.

  31. JohnM. says

    Thanks for the article clarifying the diagnostic parameters in assessing when a person is ‘pre-diabetic’ or ‘has type Two Diabetes’, after a naughty, naughty ratio with the hemoglobin A1C. I feel fine, and am a bit overweight. My doctor telling me with a ratio of 6.9 with the hemoglobin A1C, now I have type two diabetes. Well, maybe not, since like I say, I feel fine. I am a persistent walker, mover, and shaker, pardon the cliches, and used to be a long distance runner. guess my red blood cells like my Swiss ancestors, may live quite awhile. giggle, huh, a bit. I think I will lose the twenty pounds afterall, and give the ratio what not, another spin, with less gin. uhhh, sugary lifestyle. lol. John. Thanks again.

  32. Tricia says

    HI Chris,

    Just read your article and wonder if i may be a person whose hemoglobin is around a lot longer. 3 years ago i was told i was in the prediabetic range.i forget the number sorry! Anyway, i had a baby 2 years ago and did not have gestational diabetes. Is that uncommon to have a high ac1 and no gestational diabetes? (although i did have a 10lb baby). today i weigh 123lbs and am 5feet 2inches and in the past 6 months my ac1 has been tested twice and came back at 6.3 both times. Should i have my dr. give me the post meal glucose test?

    thanks!

  33. Nick says

    Hi,
    I’ve got some problems with the study you posted. So, the researchers took data from 23 subjects, who were diabetic and compared this to the normal range in the population. 23 is kind of a low number, but worse is that there was no control group. I know this is a little nit picky, but I have never been to their lab, I don’t know if the equipment they are using to determine hemoglobin lifespan is accurate. I feel that more research needs to be done before we can discount HbA1c. Specifically a larger study with a control group.
    I’m glad you are getting a conversation going about the topic, and I was not aware that this was a possibility.
    Thanks!

  34. Melissa says

    My blood sugar levels are great when I’m not pregnant, but at the end of my pregnancies (2 so far), I have glucose in my urine. My postprandial numbers are normal, but my A1c was a 6. My healthcare provider was very concerned. Here I am now pregnant with an unexpected bonus… I confess, the thought of going through so much testing again is so stressful. I feel great, and we are far from a sedentary life style (my boys and I walk 4 miles every morning). And we eat a balanced wholistic diet.

    So really what I’m saying is thank you for helping me feel normal, even though my healthcare providers insist I’m high risk. What a joke.

  35. Cari says

    I want to thank you for sharing your research, experience and knowledge. I have been diagnosed with gestational diabetes and based on how my endocrinologist approached my care, I feel pretty strongly, she was more interested in writing a prescription than providing the appropriate guidance and strategy to managing my GD.

    Also gauging from how my Mom was treated for her pre-diabetes, it seems to me that *some* of today’s doctors are motivated by external sources to diagnose and treat diabetes with specific drugs (pills or insulin). I am appalled that by the one hour test, this dr preferred to put me on a mid-range dose of Gliburide which is not FDA approved for pregnancy and only has a 10 year history of use during pregnancy. Thankfully, I am educated and confident enough to take some control in my own care and opted to attempt to control my blood sugar with better diet and exercise. In 12 weeks, I have only had 3 “high” readings and those 3 were after splurging on a refined sugar product and after 2 hours, my level was 107 or under.

    I think it’s dangerous and irresponsible for doctors to diagnose based on single test results which, as you state, do not mirror real life and so logically, cannot possibly tell the whole story. I believe if more doctors subscribed to your theory of the variety of tests to show the entire picture, we might get a better handle on diabetes, gestational or not.

    The bottom line is that the way this doctor treated me has damaged the trust I have for the care I am receiving. I encourage everyone to ask questions and do what feels right for themselves as, unfortunately, some doctors don’t have the aptitude or make the time to care enough about the individual to make the right choices for care.

  36. Stev says

    I am glad to finally find some possible answer to my puzzle. For I may have the exact opposite and potentially harmful circumstances. My fasting and post meal glucose puts me in the diabetic range and has for the last 5 or more years (age 55). Almost always it’s at least 120+ fasting overnight. However my A1C has consistently fallen in the under 5 range every six months since then as well. And neither the doctor nor anyone else I asked could explain that. So I’ve grown comfortable thinking I wasn’t really a true diabetic.

    Seeing a logical explanation now is going to get me motivated and back on track with diet and monitoring.

  37. dnarex says

    How is anemia defined? I have normal hemoglobin and hematocrit but my serum iron and ferritin are very low (about half of the bottom value of the normal range). In the past, hemoglobin and/or hematocrit have been slightly low.
    According to Mayo Clinic, low hemoglobin will give false low results on hA1c whereas low serum iron will give falsely high results. Based on that I would assume my 5.2 is higher than the result would normally be because of the low iron. If I am classified as anemic based on ferritin and serum iron, then presumably my red blood cells are short-lived and my hA1c should actually be higher. Based on hemoglobin and hamatocrit, I wouldn’t be anemic and the test would be fairly accurate.
    I am not sure how to interpret the results.

  38. Dee says

    Hi there. New to type two. Well- I was on file I was 10yrs ago but lost 33kg and it wasn’t issue so they re considered it (but u don’t get rid of it- you just manage it well). Well GD turned into type two. But 2yrs of regular hypos (daily)- I got first a1C and its 4.9%. I was anaemic after son was born born but not been tested. Iv been testing FBG, pre and post meals. Fastings 5-5.8 so not bad. Pre and post meals are my issue more so post… 8-10mmol. Hypos are happening less
    Now and I can only assume the test in June will be raised? Or is that assumption not valid? Just started metformin. 2 days ago and numbers are up! And then I feel low but I check and its up!

  39. Ashley says

    My A1C was low the last time it was taken. My doctor suggested I eat more sugar, but I already have quite a bit in my diet already. I’m a little overweight, too. Could this number be an error, and should I look into other options of raising my A1C or checking it another way?

    • Marie says

      i would look into finding a new doc. Seriously! That is the most asinine advice ive ever heard!! If you are seriously hypoglycemic (low blood sugar) which is VERY hard to see on an a1c test, the LAST thing you want to do is eat more sugar!!! Hypoglycemia is often a precursor to HIGH blood sugar, aka diabetes! Eat a normal, healthy diet, with good fats and protein, but for heavens sake get a new doc.

  40. Re says

    That’s a great relief. I lost my peace of mind with this A1C diab thing. I got 5.7 and I was told the same, insulin resistance issue could be there. Oh God, I’m trying for baby I do not want to get onto more pills n troubles.

    • Marie says

      on the positive side, if you did end up on metformin… it can raise your fertility level :). But still i wouldnt worry too much, but if you want to be ultra healthy, ditch the carbs.

  41. Angela says

    So i went to er tuesday with chest pain and palpitations. Found out i was having psvt. Thry found out from blood work that my blood sugar was 209 at the time. So i went to my dr the next morning for blood work. My a1c was 5.8 and bs was 100. He didnt seem to concerned about that. But i have been checking my bs at home, got 130 fasting and today i got 239 2 hrs after i ate a bowl of oatmeal with sweetner and a cup of decaf coffee with sweetner and cream.

    • Marie says

      Angela, honey, please stop eating like that. Please. I dont care what your doc says, that blood sugar is dangerous, it wont kill you quickly, but it will kill you. Research a high fat, low carb diet (not a low fat, low carb diet, not a low fat, high carb diet (which is what you just described) but a high fat, low carb diet. Please.

  42. Katie says

    My sister is 35 and a survivor of leukemia when she was a child. She has been diabetic for over 10yrs as a result of the chemo and radiation used for her treatment. Her daily readings are about 90-120. However, her A1C continues to skyrocket. A little over a year ago it was around 7.5 and is now up to 8.5. She’s barely 5ft and weighs only 90lbs. She’s not your standard patient since she suffers from several other late effects of the radiation, including osteoporosis. And she is very regimented regarding her diet. Any suggestions on why the A1C is so high?

  43. othelzer says

    hey have you ever read Dr. walech “dead doctors dont lie” and his reomendation of cromium and vanadium for diabetes. is this a real deal you have heard about or is it a scam?

  44. David says

    Hello Doc,

    I had a recent blood work come back with my Glucose serum at 92 and my A1c Hemoglobin at 6.1. I have made changes in my diet and excerise now. Am I at risk for diabities at 10 to 15 years from now or should I be fine? I also lost 8 pounds in the last three weeks from eating better.

    Thanks
    David

  45. Simon says

    Just got back from the docs after 2nd blood test in 6 months, started high fat, low carb (under 50 grams) and med protein in feb this year, first blood test was normal back then according to doc. Today he said you are pre diabetic and have hyperlipidemia. TC was 291 and TG 205!! HBAc1 was 5.7 (NG SP), the blood test was taken first thing 8AM after a short fast of 12 to 14 hours since night before. For 2 months have had no starches, only veggie greens and protein and fats. Now my family wants me to stop eating this way ASAP! Don’t know what to do? 46 yrs, 82kg and 12% body fat. Lost 10kg and halved the body fat in 6 months, so why am I now pre diabetic according to my doc? And must eat normally or I might kill myself….

    • Mary says

      Simon,
      I realize your post was a while ago yet would share what I was told.
      It may take a body a while to acclimate to a low carb diet.
      Richard Bernstein, MD, is a Type one diabetic who is close to 80 years old and still practicing medicine in 2014. He went low carb after he was almost killed by what he was told to do initially after diagnosis.

      Hope you were tested again before freaking out!!

  46. Hughena N says

    My first a1c test was 5.9. My doctor ordered a glucose tolerence test .My fbg was 94 and my 2hr post after 75 grams of glucose was 105. My a1c at that time was 6.2. I weight 128 lbs . I have lost about 7 lbs from when the first a1c was done until my the second one. Do I have something to be concerned about? There is diabeties in my family.

  47. Patricia says

    I had gestational diabetes with my last two kids. I have been eating healthy and walking five days a week for one hour. In January I had a A1C done,I had a 107 glucose and my A1C was 5.6. I had it done again two weeks ago now my glucose is 79 and my A1c is 5.7. I lost 45 lbs. Why did my a1c go up? My doctor said I am fine. He also did other lab work and everything came out fine. I dont want to become a diabetic thats why I am taking care of myself.I dont have high cholesterol. How often should I check myself?

    • Chris Kresser says

      A1c isn’t a particularly reliable marker for individuals as I’ve pointed out in this article. I’d go by your fasting glucose and, more importantly, your post-meal glucose. If you’re staying below 140 mg/dL one-hour after meals and 120 mg/dL 2-hours after meals, that’s a good sign.

      • Mary says

        My understanding is that a 2 hour window and a 3 hour window will give more accurate readings, especially for someone up in years and/or with some type of digestive difficulties.

  48. ICDogg says

    BTW I’m not a big Wal-Mart guy either but they do have home a1c tests that are about $9. You send your sample to a lab and get the results on-line. I did one the same time I had one from Quest Laboratories and it came within 0.1.

  49. ICDogg says

    Thanks for the info explaining long-lived RBC. This would explain the extended lag time for lowering my a1c, which continues to get lower each time I test it but not quite as quickly as I expected based on the assumption of an “average of the last 2-3 months”.

    6 months ago I was over 13, I’m just above 6 now, trying to get under 6.

    I do test regularly an hour after meals, and it is never over 130, as a result primarily of low carb eating.

  50. Steve says

    “Another condition that affects hemoglobin A1c levels is anemia. People who are anemic have short-lived red blood cells, so like diabetics, they will test with falsely low A1c levels.”

    FYI Iron deficiency anemia actually causes an elevated A1c. This is a common misconception. Providers sometimes believe pts with microcytosis or a low MCV anemia, that the binding of sugar to the heme group is lesser than normal MCV levels or that the smaller the RBC some how reduced the A1c % concentration. Research shows the opposite is true.

    • says

      I am a 73 year old male with early stage MDS. My RBC is 11.4, fasting BG is 133, and A1C is 7.9. My doctor says I need to start medication to manage my BG. What do you think? Do you think I can manage my BG levels with diet and exercise? I currently am on a diabetic diet and ride a bicycle about 30 minutes per day. I also walk about 30 minutes a day. My weight is 200 and I am 6 feet tall. My cholesterol and triglycerides are normal.

      • Marie says

        *I* think that a “diabetic diet” if you mean the ADA diet, is the worst possible thing for diabetics. Try low carb high fat, and keep your carbs down to around 30 a DAY, with no bread, sugar, pasta, or simple carbs, choose low glycemic veggies and a few berries for your carb count and you WILL reduce your blood sugar. Go to diabetesforum for support and tons and tons of advice and recipes, tell em I sent ya :)

  51. Rose says

    I had my AC1 test without fasting and the reading was 6.8 my doctor already wants me on metformin, can I try diet and exercise first or should I not wait and get on this medication. My glucose in my urine is at normal levels (84) Please advise

    • Marie says

      you can ALWAYS try diet and exercize first!! Look up Low Carb High Fat and diabetes and do what it tells you, guaranteed your a1c AND your real blood sugar will drop :)

  52. Martin Bratcher says

    Hi Chris,

    Thanks for the great article. I am 34 yrs old and recently was diagnosed with type-II. My first A1C was 7.3 and the latest A1C i.e. my second was 5.5. However, I used to check my sugar level using glucometer during last three months – each day one reading – 1 hr before and 1 hr after (fasting, lunch, supper and dinner) and it consistently averaged 170-180. But suprisingly, my A1C was only 5.5. I also tried my glucometer with one other glucometer couple of times and it seems to be same. Do you think this is normal and I should rely A1C result (irrespective of the fact of RBC’s life). Do you think fructosamine test would be more reliable for me?

  53. James A says

    I just got back an A1C of 5.8, which shocked me. I spent a few weeks testing my fasting blood sugar, and it ranged from 75- low 90’s. I also have tested my postprandial levels at 1 hr and 2hrs after purposely high carb meals (for testing purposes only). Prior to eating, I had an 84 mg/dl, then I ingested a bagel, 2 cookies, and a tall glass of orange juice. One hour after, I was at 123 mg/dl, and 2 hours after, I was at 98 mg/dl, and 3 hours after, I was back in the 80’s.
    My question is, my prior A1C was done during a routine physical in 2009 , and resulted in 5.2 . The blood work was done by Lab Corp, which stated a reference range of 4.0-6.0. This time, my doctor’s office ran the blood work themselves, and I resulted in a 5.8, and their reference range is ” 5.5% – 7.0%”. Could this mean that if my blood work were tested at Lab Corp again instead, I may have had a lower A1C?

    • Chris Kresser says

      A re-test wouldn’t hurt, but as I said in this article it’s not an especially reliable marker in individuals. If your fasting and post-meal blood sugars are consistently low throughout the day, I wouldn’t worry about a slightly elevated A1c.

  54. lue ann says

    I have anemia and not much appetite. I recently had an A1C test and my Dr. said my A1C was 6.3. I am freaking out because he also said I am pre diabetic. I test my blood glucose 3x a day and it is always in the high 80’s in the morning, 90’s at lunch and night.

    • Chris Kresser says

      You need to test your blood sugar just before a meal, and then at 1- and 2-hours after. If you’re below 140 mg/dl at one hour and 120 mg/dl at two hours, and your fasting glucose is normally in the 80s, I don’t think you need to worry much about your A1c. As I said in the article, it can be affected by red blood cell turnover, which would be altered in anemia.

      • maureen says

        Hi dr. Kresser
        I have a number of autoimmune diseases. 12 in fact. Today I saw a new specialist for my diabetes. I have had 3 blood transfusion in the last six month. I have ever scope you can think of each time. I even swallowed the capsule camera and there is no sign of bleeding anywhere. I have celiac and biopsies were taken during the scopes and the results turned out to be normal. My blood sugars are uncontrollable at times If stressed they rise to the high 20s and if I take insulin before I get home I am having a low at 1.9. I will get up, blood sugars at 6, eat breakfast and take 5 units of humalog and get to the doctors and my blood sugar all have risen to the high 20s. Today the doctor mentioned in passing that it could be my body is rejecting the insulin. Can you explain this.
        Maureen

        • says

          Hi dr. Kresser
          I have a number of autoimmune diseases. 12 in fact. Today I saw a new specialist for my diabetes. I have had 3 blood transfusion in the last six month. I have ever scope you can think of each time. I even swallowed the capsule camera and there is no sign of bleeding anywhere. I have celiac and biopsies were taken during the scopes and the results turned out to be normal. My blood sugars are uncontrollable at times If stressed they rise to the high 20s and if I take insulin before I get home I am having a low at 1.9. I will get up, blood sugars at 6, eat breakfast and take 5 units of humalog and get to the doctors and my blood sugar all have risen to the high 20s. Today the doctor mentioned in passing that it could be my body is rejecting the insulin. Can you explain this.
          Maureen

  55. says

    Great article Chris! Thyroid can also skew the results due to its effects on erythropoiesis. I have a few hypothyroid patients with normal fasting and post prandials whose a1c’s were elevated. After getting them from hypo to euthyroid, A1c came down! Just another interesting tid bit!

  56. Debbie Gries says

    hi – I am like others and have been freaking out b/c my practitioner told me I was pre-diabetic with a HgA1c of 6.0 but my triglycerides are only 55 and HDL is 68, over all chol 198. I am 5’4″ and 125 lbs. Yes, I eat sugar and wheat but also eat veggies, good fats, etc. The 6.0 just seems so out of whack compared to my other numbers which have actually improved over the last year. Should I investigate more or just have another test in 3 mos. (I am making sure to exercise at least 30 min 5 days/week)? Thank you!

  57. Afshin Siadat says

    Hi Chris, Interesting article you have. I have a lot of interest in this subject because I was concerned with my blood test that I had this past October. I am a 22 year old male in good standing health. I was shocked to see that my hemoglobin a1c level was 5.3%. The fasting glucose was 83 and I started to test my blood glucose at home with a home tester, and the highest 1 hour glucose reading I had ever had post-pranial was 134, and most often my one hour reading is between 90-120 depending on which type of carbohydrates I had eaten. Those seem to me based on my research as a person with a normal range. The main reason for my post is I was hypothesizing that maybe the fact is that I have high blood hemoglobin levels, and I am a competitive athlete, that is it possible that I have red blood cells that live much longer than 120 days? Do athletes that do a lot of altitude training in order to increase their oxygen uptake increase the lifespan of their red blood cells, thus verifying why my hemoglobin a1c was over 5%? My next blood test I am going to do a fructosamine to have a comparison. From the best of my knowledge, the highest fasting blood glucose I have ever recorded was 85 when looking at all my blood tests from age 15.
    Thanks,
    Afshin

    • Chris Kresser says

      An A1c of 5.3 is perfectly normal. That’s nothing to be concerned about. Your other blood sugars are normal as well.

      • phileda erskine says

        April 2012 A1c was 4.1
        August 2012 A1c was less than 4.1

        I’ve lowered my Lantus dose and will get lab test in 90 days.

        Is Is there anything else I should be doing?

        What are problems/risks with this A1c level?

  58. Deborah Henderson says

    Hello I am awake and can’t sleep because my Dr. thinks I may be prediabetic! My finger pricks taken over two weeks show after a full meal at the end of the day 80 or 85 . But when I had a fasting (2x’s) Blood work my Blood Glucose is 6.3 . I am home and had to retire due to a back injury fom work and this has limited my activity levels so much. I am slightly overweight , my chol is a little high 230 my trigl are good and my good chol is good . Can I really be pre diabetic or can it be from the pain meds and other meds I take fo asthma ,that I got when I was 40 from severe re-flux(had surgery fo reflux in 2005) Last I took advir disk 250/50 just before fasting Blood work . No family member ever had diabeties, high blood pressure ,high chol ,yes! I’m scared. Thanks so much

  59. Maria says

    Hi Chris,

    I’ve heard conflicting results about the effects of iron-deficiency anemia on A1c levels. I had an elevated A1c of 5.8, and my GP said that anemia falsely lowers A1c, while an endocrinologist said it can falsely raise it. My ferritin level at the time were very low (4, since increased to 14). I’m a runner with a low BMI and low blood pressure and no other indications of metabolic disorder. Can iron-deficiency cause a falsely high A1c?

    I’ve also struggled with amenorrhea for over a year (PCOS has been ruled out). Can anemia can affect menstruation? Again, I’ve gotten conflicting responses from my doctors.

    Thanks!

  60. Matt says

    Just got my first lab test back (life insurance required it). Since starting low-carb, high-protein 9 months ago, and regular CrossFitting, I figured I’d have stellar results.

    Glucose: 80
    Fructosamine: 1.73 (HIGH)
    Hemoglobin A1C: 4.8

    Because I was told not to eat/drink for 6hrs, I don’t have a post-meal glucose level. Anyway, the fructosamine level is freaking me out. I’m 5’9″, 155lbs, with very little body fat. Should I be concerned? I bet my life insurance company is doing to ding me.

    • Marie says

      hmph. I saw “June 22″ and i thought the post was from YESTERDAY.. not yesterday three years ago LOL. oops.

  61. Anup Kumar Mukherjee says

    Thanks for this information. My A1c generally varies between 6.3 to 7.3 and my fasting sugar remains around 75 to 90 but my PPsugar, two hrs after meal is always between 250 to 270. It never goes down to 200 level. I am on insulin and any higher dose leads to hypoglycemia. Interestingly the ppsugar drops very fast after 3hrs. Is it a delayed action? So how ppsugar can be taken as an yardstick?

    • Marie says

      it nosedives because your insulin has kicked in. MOST peoples blood sugar starts dropping around the 2 hour mark, it takes us longer because we have to wait for the second wave of the insulin to clean up what the first wave left behind. What kind of insulin are you on? Lantis type? Humalin? Humalog? one of the ultra fast acting ones? (im not on that one so i cant remember the names, starts with an A i think lol. ) minute adjustments can usually be made to Regular or fast acting insulin types to avoid blood sugar that is that high, and a low carb diet helps tremendously. My sugar used to be like yours, type 1 insulin dependant diabetic, i figured there was nothing i could do… then i went low carb. Seriously, it is a big change, but blood sugars above 140 are what cause major organ damage and lead to ALL the bad stuff diabetes is known for, and it killed BOTH my parents, who were basically middle aged, certainly not elderly. (dad was 56, mom was 61 when they died…) Dont be like them. The bread, sugar, and pasta are soooo not worth it, neither is the fruit. And there is sugar free chocolate that tastes pretty good these days LOL.

  62. says

    I love how your posts bring enough science to the forefront so that practitioners (like myself) can make us of it but so that the everyday person can read it and make some sense of it as well. This is a very thorough overview of a marker a lot of us are watching with our clients, so thanks!

  63. Beverly says

    Thank you for the clear explanation. My fasting blood sugar has always been quite low. I participated in a “Community Health Fair Screening” and they sent me a letter telling me I had an A1C of 5.7 and was pre-diabetic. I was a little freaked out! Then they sent a letter saying there had been irregularities that day, and everyone needed to be re-tested. I was reluctant to go to them again, given that I was just a little annoyed. I went to my doctor who again checked my fasting blood sugar. It is low, as usual. She said she would not recommend A1C unless fasting blood sugar was elevated. She also said that getting that test done would indicate that I was suspected diabetic, and that would not be good to have on my medical records. I was still a bit concerned, but your explanation has made me less concerned. I can see how both the numbers could be accurate, and not in conflict. Thank you.

  64. Kelly A says

    Thanks so much! That explains why my A1c is always around 5.6 when checked every 6 months but my glucose readings were great on the nasty 3 hour glucose tolerance test, despite eating lowish carb until a few days before the test and definitely not accustomed to such a large bolus of sugar.

  65. Curt says

    THANK YOU! I’ve been trying to figure out why my A1C was higher than it should be (close to 6) after a three months of very strict paleo. Now – 9 months into paleo – I rely on a glucometer. Those numbers are great. Fasted is usually in the mid 80s. Virtually every meal I consume keeps me under 110. I’m pretty confident saying that my BG has not been above 120 in the past 6 months and is actually rarely even over 100.

    One weird thing though: My waking BG is one of my higher readings of the day – mid to upper 90s. I actually rises during the night. Sleep is solid, chow is great, exercise is good. Not complaining too much. 9 months in and I’m down 60-70 lbs, BP is down about 30 pts sys and dys, and bloodwork is great. I have plateaued pretty hard the last 2 months. Gotta figure that one out.

    Thanks again! This explanation of A1C is super helpful!

  66. says

    @Barbara and Susan.

    All health measurements are contextual. If you are eating a diet that has some carbs in it, and your A1c and fasting BG are both high – they are concordant and telling you the same thing – you have poor glucoregulatory control. No need to confirm with fructosamine when fasting BG is high also – over 100 is high.

    Eat VLC with enough low GI carbs to stay out of ketosis – split between lunch and dinner.

    Magnesium 400 mg/ day as citrate (cheaper) or malate.

    Resistance exercise 1-2 x per week.

    Try that, and if numbers don’t come down in a few months, talk to your doctor about metformin

    • Marie says

      Wait, why keep OUT of ketosis? You know, of course that benign dietary ketosis and ketoACIDosis are very different things and have nothing to do with one another except the word “keto” lol. There is nothing wrong with a diabetic being in ketosis, i strive for that, and it is always accompanied by LOW blood sugar, while ketoACIDosis, is always accompanied by very HIGH blood sugar and is very very bad heh.

  67. says

    I’ve been warning about this for some time, but not had time to post on it. This is another example of using a statistic that is useful for populations for individual evaluation – and it can be very inaccurate for the individual. One reason that I stress avoiding lots of measurements.

    I think it’s possible that with reduced oxidative stress red cells could live even longer than normal, as I see perfectly healthy people on PaNU/ Paleo 2.0 diets all the time that have this pattern – low pp BG, no history of DM, good body comp, etc. They have an A1c of around 5.8 or so, then they read Jenny Ruhl or Bernstein and think they are going to die. In my experience, the diabetics or those with history of metsyn seem to achieve lower A1cs than the formerly healthy. There is just no logical reason to think a type I diabetic on Bernstein’s diet is with A1c of 4.8 is actually healthier than a non- diabetic would be on it with A1c of 5.6. I favor red cell survival as accounting for the difference, but it may have to do with de-glycosylation enzyme activity as well – we have such enzymes trying to undo the damage and their activity may depend on how much oxidative damage is going on – pure speculation on that.

    As far as recommendations, I recommend getting A1c and if it is below 5.5 you are done. If it is 5.5 to say, low 6s, do 24 hr and pp bg with fingersticks. If it is much above 6, then confirm it is high with fructosamine.

    PS – for reference, my A1C is 5.6, Stephan Guyenet’s is 5.8. Peter’s is 4.8. Peter is the only one who was ever overweight or had signs of metabolic syndrome among the three of us. Purely anecdotal but interesting. I did a 24 hr BG when I ate VLC and when my A1c was 5.6. The actual BG values correlated with an A1c that should have been about 5.0.

    @Robb

    I was planning to discuss this on your podcast, but it hasn’t happened yet ;)

    • Lexi says

      Thank you, thank you. I know this is old, but I must say I have learned a lot from both CK and Kurt Harris. Thank you for this comment. That is me, 5.8; and now I can stop thinking about it.

  68. susan says

    i have similar numbers to barbara above, and also wonder how worried to be. i am about 35 lbs overweight so i know that’s part of it but i remember being surprised when i attended a pre-diabetes class at kaiser that at least half of the folks there were normal weight or even quite thin. my fasting BG has ranged in the upper 90’s to low 100’s for several years now.

    • Amit says

      Yes Susan! You have to start taking care of yourself! You should visit doctor and see if he suggests you some medication! I had sugar of 126 but HbA1c of 5.7, but still my doctor suggested me medications, exercise and controlled diet… by Exercise I mean brisk walk is also fine but on regular basis. Also I followed 5 things he had to tell me to pay attention to… No Potato, No Sugar, No Fine Wheat Flour.. thats Cake and white bread and stuff.. brown bread is alright in small amounts.. say 4 slices in breakfast is alright.. Drink Lot of Water… and Exercise regularly… and I was able to reduce 20 Kilos in 6 months…. and I am in a healthy range now… things are fine.. and I am off medication… I had to take 6 tablets a day before… Hope this helps.

  69. barbara shapses says

    Last week my doctor told me I had an A1C level of 6.8 and my doctor told me to lose 20 lbs. My glucose level was 105. Do you agree with my doctor

    • Amit says

      Yes Barbara! You have to start taking care of yourself! You should visit doctor and see if he suggests you some medication! I had sugar of 126 but HbA1c of 5.7, but still my doctor suggested me medications, exercise and controlled diet… by Exercise I mean brisk walk is also fine but on regular basis. Also I followed 5 things he had to tell me to pay attention to… No Potato, No Sugar, No Fine Wheat Flour.. thats Cake and white bread and stuff.. brown bread is alright in small amounts.. say 4 slices in breakfast is alright.. Drink Lot of Water… and Exercise regularly… and I was able to reduce 20 Kilos in 6 months…. and I am in a healthy range now… things are fine.. and I am off medication… I had to take 6 tablets a day… Hope this helps.

      • Mary says

        Amit,
        Let your Dr. eat 4 slices of toast for breakfast.
        For the rest of us, I would not go over 1 or 2.

        Think gluten as well as blood sugar

        • Marie says

          Yeah, im going FOUR SLICES??? hehehe. Especially at breakfast! Btw, white vs wheat, if we are talking grocery store bread…=no difference, and with diabetics, its all poison, hehe. Thats ok though, after a while you realize bread has no flavor, especially sandwich bread, so who needs it? Just put the butter RIGHT on the eggs, much better lol. And i got my blood sugar down over 300 points. Yes, that is two zeros.. 300 points lower than it was. Yay low carb high fat diet!!

  70. chriskresser says

    Glad it was helpful, Robb. A1c was my nemesis for quite a while. Couldn’t explain strange blood sugar patterns I was seeing.

    Alex: CRP is a good measure of systemic inflammation, and has some correlation with CHD, but lowering CRP doesn’t necessarily lower CHD risk. So there’s some murky water there.

  71. qualia says

    last time my A1c was 5.2% – which is 4.8nmol according to my lab report – which is 86mg – which is pretty much my usual fasting level. so why would all the labs and docs still use A1c if it really was THAT unreliable (especially in pre-diabetics)? what would keep them from switching to fructosamines a long time ago, or at least routinely measure both (they’re both rather cheap)? i mean, 3 weeks of average sugar is still plenty to get an overview, or not?

  72. says

    Hi Kris,

    Great article, I think this really clears up what has been going on with me.

    You might recall a couple months back- I was asking about why my A1c was 5.7 when I am full ancestral/paleo nutrition for over a year, lowish carb, 10% body fat, and a competitive athlete. HDL was over 100, triglycerides about 40, CRP less than .1 . My blood sugar levels never went over 120 even after meals and were usually around 86 fasting, but because of the 5.7 A1c my doctor said that I was close to prediabetic levels!

    It freaked me out to be honest, so I did a bunch of research and decided that I must just have long-lived RBCs. It’s good to hear that this is a fairly common occurrence, and this makes a lot more sense.

    Now I’m going to go listen to the Robb Wolf Podcast, I’m excited to hear it.

    Tyler

Join the Conversation

Current ye@r *