Diabetes Self-Management Blog

If you’ve ever wondered how your HbA1c level relates to the numbers you get on your blood glucose meter, help may be on the way. A recent study has found a more accurate way to "translate" HbA1c results into average blood glucose levels. In the near future, therefore, doctors and labs may be reporting HbA1c test results both as a percentage (the old way) and as an "estimated average glucose" (or eAG) number.

The HbA1c test, which is a measure of blood glucose control over the previous 2-3 months, measures how much glucose is bound to hemoglobin in the blood. It is expressed as the percent of hemoglobin molecules that have glucose attached. Typically, people who do not have diabetes have an HbA1c value of less than 6%; the American Diabetes Association (ADA) recommends an HbA1c goal of less than 7% for people with diabetes in general and lower goals for some individuals.

Now, the “International A1C-Derived Average Glucose” (ADAG) study has found a simple mathematical formula that can “translate” HbA1c levels into an eAG level expressed in milligrams per deciliter (mg/dl), the same units that people use when they monitor their blood glucose at home. (It can also translate HbA1c into an eAG in millimoles per liter [mmol/l], the unit commonly used outside of the United States.) The study was presented on June 7 at the American Diabetes Association’s Scientific Sessions; it has been published online in Diabetes Care and will appear in print in the August issue of the journal.

The study took place in 10 centers and enrolled around 500 volunteers of various races and ethnicities. The volunteers consisted of 268 people with Type 1 diabetes, 152 people with Type 2 diabetes, and 80 people without diabetes. The researchers used a combination of continuous glucose monitoring and frequent blood glucose monitoring (seven times per day) to measure people’s average glucose levels; they also checked their HbA1c levels in a central laboratory for three months.

By comparing these results, the researchers were able to develop a mathematical equation that accurately converted HbA1c levels into average glucose levels. They found the calculation to be about 84% accurate in all the different subgroups studied. The researchers point out, however, that people of African and Asian descent were underrepresented in the study, and that some groups of people—children, pregnant women, people with red blood cell disorders, and people whose diabetes was not in stable control—were not included in the study.

Why is this new number necessary? The researchers believe that an average glucose level in the units that people already use for self-monitoring will be easier to understand and will make it easier for people and their doctors see how to adjust their treatment.

It may take a year or more before eAG values start to show up alongside HbA1c values on lab reports across the country; this is because new software will need to be disseminated and loaded into lab machines. In the meantime, though, there are a few ways that you or your doctor can convert your HbA1c level into an eAG value now:

  • Go to www.diabetes.org/ag. There, you will find an online calculator that can convert HbA1c values into eAG values in mg/dl or mmol/l and vice versa; you’ll also find a chart equating HbA1c values between 6 and 10 with eAG values.
  • Plug your HbA1c into the formula yourself:

    28.7 x HbA1c - 46.7 = eAG (in mg/dl)

  • The ADA is also starting to provide handheld calculators to doctors that will allow them to calculate eAG values easily in the office.

Will eAG replace HbA1c down the road? The researchers who conducted this study think that it may. However, the eAG is just a new way of interpreting the same information provided by the HbA1c, and HbA1c values will still be reported by labs for the foreseeable future.

For more information about interpreting your HbA1c level, see the article “H-B-A-1-C (What It Is and Why It Matters).”

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Comments
  1. Why is so much money being spent. If you can convert from A1C to eAC it isn’t anything new. If I take my last A1C of 5.5 x 27.8 - 46.7 = 106.2. If I look at the old conversion chart 5.5 = 105. I don’t see that we are gaining anything. LOWER is BETTER

    Posted by s6954118 |
  2. Looks like there’s a typo in your formula. The ADA site says ‘28.7 X A1C - 46.7 = eAG’, not 27.8.

    Posted by David |
  3. Invalid Study

    To do any study about diabetes with only 500 people is pure folly, considering the number of diabetics out there! Furthermore, out of that number, only 268 had Type 1 diabetes. This represents too small a number to be of any statistical significance.

    It is my sincere hope that people with diabetes will write to the ADA and to their doctors with requests not to use the results of this foolhardy study.

    This is also not new or revolutionary. Other mathematical formulas, with slightly different results, have been around for more than six years. As this study has only an 84% rate of accuracy, that is too much for me. And, it doesn’t take into account those people who have both very high and very low Blood Glucose numbers. An “average” by itself, is meaningless. Also, most doctors, and informed patients know what the
    averages are without the need for this misleading study.

    Posted by *~*Wisewords |
  4. Re: this blood glucose standards war, see

    http://www.diabetesmine.com/2008/06/eag-estimated-average-glucose-glucose-standards-war.html

    Posted by AmyT of www.diabetesmine.com |
  5. Thanks, David–I’ve corrected the formula.

    Posted by Tara Dairman, Web Editor |
  6. What is the big deal? You still have to know the HbA1c in order to calculate the eAG. If you can not understand the relationship between the percentage HbA1c and your Blood Glucose levels and its impact on your health. Why would you be any more likely to understand new value that utilizes that same HbA1c in its calculation? The HbA1c is not going away no matter which you prefer. Those of satisfied with HbA1c will continue to utilize it and those who think eAG is the “answer” can ignore the HbA1c once they have done the calculation. This is just a tempest in a tea pot!

    Posted by buzzart |
  7. The new eAG is closer to whole blood glucose averages and I prefer the plasma averages since meters are made to give out the plasma equivalent.I do not feel the study covered enough people to be accurate enough. There are just too many factors that were not figured into the equation. I wills tick with hba1c for now.

    Posted by deafmack |
  8. Where’s the BENEFIT to the eAG???

    If I want my Average Blood Glucose, I can get THAT by simply downloading my GLUCOMETER readings into my computer, and telling the software to display my AAG (Actual Average Glucose) at MUCH LOWER COST than the cost to get the HgA1c test, then use a formula to arrive at an ESTIMATED Average Glucose reading…

    But then again, I can also CALCULATE my Estimated HgA1c using my meter’s indicated Average Glucose reading.

    And over the past THREE YEARS, EVERY TIME, my calculated A1c result has ALWAYS been within 0.2 of the blood test resulting A1c reading. Meaning my formula to calculate my A1c reading based on Average Glucose Reading has proven at least 95% more reliable than their formula to arrive at an Average Glucose Reading calculated from the A1c test result.

    Posted by rcmodelr |
  9. The A1C is a plasma blood result that is done in a lab. I believe a blood sugar average from this result would be easier for patients to understand. Most patients seen in our Diabetes Education do not understand what an A1C is. I am in favor of the eAG.

    Posted by Annette |
  10. Tara,
    Can you tell me about how long I should wait after donating red blood cells before the A1c test results would again be accurate? I assume that the donation of red blood cells would affect the A1c results, but I could be wrong. (I donate two bags of red cells and they return the plasma.) I trust your organization would be aware of any impact donation would have on the A1c.

    Posted by stuartgoldman |
  11. sir there, I printed five pages , and second page with blank column, it printed match mixed in third page. printed about what’s your eAG? you’ll know soon….

    Eugene Zenzen

    Posted by ekzen@aol.com |
  12. Hi Eugene,

    To print more easily, click on “Print” up at the top right-hand corner of the blog entry (next to “Text Size”). This displays the Printer-friendly version of the entry.

    Posted by Tara Dairman, Web Editor |
  13. i am 80 years old man .i feel so week,and i can not walk even any some setps how can i improve my self through medicen or etc.

    Posted by malik |
  14. I had a %HA1C score of 6.3 and the Ref. Range/
    Males is 4.8-6.0 %. the eAG is 133. My doctor
    said that I’m pre diabetic. She is entering
    me in exercise class at our hospital. It consists
    monitored exercise–treadmill, stationary bicycle
    ect. She also recommed a brisk 20 minute walk
    daily and meal plan of 2000 calories daily and
    only sugar free sweets (Splenda) I already have
    kidney damage that resulted from uncontrolled
    high blood pressure. My last lab(renal panel)
    Glucose 113 Bun 34 Creat 1.50 ECO2 33.0 CGFR
    46. My blood pressure is finally under contol.
    I fear thinking about dialysis. I take alot
    of BP medicine. It’s funny most all medicine
    doesn’t cure anything. I wonder if some medicines
    don’t cause other medical problems. If anyone
    would take the time to comment I would appreciate
    any suggestions. I’m sure other people have
    problems such as mine.

    Posted by Bill Wallace |
  15. Hello Bill,
    I am glad your blood pressure is good now! You are right just about EVERY medication creates new problems by their side effects. Sometimes weighing up the difference in favour of benefit versus harm is the only thing left. How ever it is often convenience, laziness on the part of the doctor, not only the patient who goes for the pill. One of my friends is the case in point. His doctor lets him down but he is dependent on him by blind faith and walking distance convenience. He told him once he is taking the same medication himself he was to prescribe to him as an encouragement. (The doctor is about 62, overweight and recently had a fall the receptionist told my distressed friend who suspects he may had a stroke). Allopathic medicine is important and valuable saving lives, extending lives. So are medicines but not all new and competing brands are necessary and some are in fact not much use AND DEADLY as it turns out. The unfortunate animosity between allopathic and complementary modality of healing limit that patients get the best help. Both camp has their wisdom but also their share of charlatans. Neither camp has the monopoly on healing. The intelligent approach is TO FIND OUT THE CAUSES OF THE ILLNESS OR EPISODES AND DEAL WITH THE CAUSE. Allopathic medicine is not too keen on that. The pharmaceutical industry controls medical education and practice. Time to time a scandal breaks out about corruption, or ineptitude of the FDA or medical boards.
    This leaves us to take charge of our health issues, learn about our conditions, ask questions of the doctors and check out their answer, so we can give informed consent. Some of us are unable to do this, and for them we need to become their advocate sharing our humanity. You can do a lot to control the blood sugar but beware of predatory claims to get into your valet. EAT MINIMUM CARBS, EAT PLENTY VEGETABLES AND SOME FRUIT EAT MEAT AND FISH FROM CLEAN NATURAL SOURCES, TAKE GOOD SUPPLEMENTS IF YOUR BLOOD TEST REVEALED LACK OF VITAMINS OR MINERALS. EVENING MEALS (NOT TOO LATE) SHOULD BE PROTEIN, VEGETABLES AND A GLASS OR TWO RED WINE ESP. CABERNET SAUVIGNON. TO YOUR EXERCISE ADD TO THE 20 MINUTES YOU DO A BURST OF REAL BRISK WALKING OR JOGGING TILL REACHING 75% OF YOUR MAXIMUM HEART RATE (FORMULA: 220 MINUS YOUR AGE AND 75-85% OF THAT HEART RATE). My blood sugar started to creep up The doctor would put me on metformin I did not fancy and now it is excellent fasting around 4.5, 2 hrs. after meals around 6-7. Good luck! Be well!

    Posted by Joseph Putnoki |
  16. To get the your average, you just at up all your readings and divided by the number of readings?

    For the month of December my total of all the readings was 7746 that was 65 readings, so I did
    7746/65=119 is that the correct way to do it.

    119 would translate to 5.8, does not seem correct. My last A1C was 7.3, I would like to think I was that good during the holidays.

    Thanks for your help.

    Posted by Gene McKinney |
  17. Gene,

    Sounds like you are on the right lines, but a Hemoglobin A1C value indicates your average blood glucose level during the past 60-90 days. So even though you averaged 119 mg/dL during the past month, you may want to calculate your average for the past 60-90 days and then see if your A1C falls within that range.

    Best regards,

    John

    Posted by John Smith |
  18. My eAG was 131 is that a high? Thanks

    Posted by Pat Foley |

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