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scottinnh
Thu, Feb-20-03, 14:01
Is the numbers used by those outside the US for their BG tests based on the numbers used for the 3 month A1C number?

In other words, if you go 3 months at 7.2 mml average every day, can you expect the same number for the A1C test? :confused:

Obviously I know it is related as in the higher your BG is the higher the A1C number will be...just wondering if it is on the same scale....

Lisa N
Thu, Feb-20-03, 15:56
Yes, that's pretty much it. To convert the A1C to US lab results multiply by 18, so that 7.2 would be a blood sugar of 129.6 (round up to 130). Not too bad, but you want to shoot for a 6 or lower (my last A1C was 5.3 :D ). As an average, 130 is still a bit high because that means that your post meal blood sugars are still going above 140 (probably higher) and you don't want that.
Also, the A1C shouldn't replace daily testing as your post prandial readings are the most important (you want to reduce those spikes as much as possible!). Studies have shown that those who do post prandial testing are more successful at lowering their A1C readings because they are getting good feedback on how what they are eating is affecting their blood sugars and making reductions as necessary. :thup:

kjturner
Fri, Feb-21-03, 01:05
Are you a mind reader?? I posted the very same question over on another diabetes forum yesterday :roll: !!

Cyprinodon
Wed, Mar-12-03, 15:47
There is a comparison chart on this page (scroll down):

http://www.childrenwithdiabetes.com/d_0n_040.htm

Lisa N
Wed, Mar-12-03, 19:50
Yikes! They consider 150 "slightly elevated"??? I would be very unhappy if my blood sugars were that high at this point.
Of course, if you've been running a consistent 300, 150 would be a great improvement, I guess, but research has shown over and over that cell and organ damage begins when blood sugars go over or remain at 150 or higher for any length of time.

pepsi max
Sun, Jul-13-03, 03:09
could somebody please clarify the a1c results for me please as it is driving me insane. in another thread entitled-newbie q about hg1a carolync wrote-a1cs at 5.7=126mgs.i thought to get the results in mgs you had to x the number by 18 and this would give the average bg reading over the last 3 months. after clicking on the site carolyn posted i saw what she meant however i,ve just come acoss this thread and lisan says to convert a1cs to us lab results, x by 18 which would give an average bg of around 100.now i,m more confused than ever and up till yesterday i was quite happy with my hba1c of 5.3.now i find that carolyns way i have an average bg of 111, which i,m not pleased about, on the otherhand,lisaNs way my average bgs would be<100.please help.i,m now confused.

CarolynC
Sun, Jul-13-03, 06:47
I stand by my statements from the post yesterday at

http://forum.lowcarber.org/showthread.php?t=122071

HbA1c values are in units of % hemoglobin in the blood that has glucose attached. Glucose in blood plasma, using the non-US units, is mmol, which stands for milliMolar and means millimole of glucose per liter of blood plasma; this is the free glucose molecule that is NOT attached to hemoglobin. These units are very different. Unfortunately, confusion arises because the magnitudes of these numerical values are similar, although they are definitely not the same.

To convert a mmol value of glucose in blood plasma to the US units of mg/dl (milligrams of glucose per deciliter of blood plasma), multiply by 18.

To convert a HbA1c value to blood plasma glucose in mg/dl, the conversion formula is:

Plasma Blood Glucose = (HbA1c * 35.6) - 77.3

An easier way to do this is to use conversion tables such as the one Cyprinodon posted earlier in this thread or the more extensive one at:

http://www.geocities.com/diabeteschart/bloodsugarchart.html

This site also includes other pages that discuss HbA1c and glucose in blood plasma measurements.

Here's a link to another webpage on this:

http://diabetes.about.com/library/blforms/blA1ccalc.htm

BTW, diabetes.about.com also links to numerous informative pages on blood sugar tests.

rainne
Sun, Jul-13-03, 08:25
That's an excellent explanation, Carolyn.

In the diabetes program I took, the nurse who taught the class demonstrated what the HgA1C tested for. She had a huge hemoglobin molecule made out of red felt and stuffed.

Around the edges, the molecule had velco.

She explained that glucose - a bag of cotton balls - is sticky, and as the hemoglobin molecule journeys through the system, some glucose is going to stick to it. In a system dense with glucose, more sticks (and she demonstrated that by putting several cotton balls on the Hg molecule)

The HgA1C test measures how much glucose the hemoglobin picks up - and therefore gives an excellent snapshot of what average glucose levels have beeen over the previous 3 months -which is about the life span of an individual hemoglobin molecule.

Normal is said to be less than 6%.

We also learned that each percentage decrease above 6 reduced the risk of complications by 30%. Which is a major factoid, IMO. So even going from numbers too high to a lower number too high is still a really good thing. Go from 12% - 11%, and reduce your risk by 30%. Go from 6.5%-5.5% and reduce your risk by 30%.



A blood glucose test will show how much glucose is floating around in the blood at a particular moment in time, and as we all know, that can change within minutes.

pepsi max
Sun, Jul-13-03, 12:15
thank you both for taking the time to clarify this for me(again).as i,ve always thought it was worked out the same as lisa n did it,i had no reason to look it up.now i have the charts,printed and digested, i won,t be going insane anymore.one more thing-i,ll be giving a copy to my diabetic nurse as she was the one who told me the hba1cs corresponded with mmols.

CarolynC
Sun, Jul-13-03, 13:31
You're welcome, pepsi max!

Perhaps part of the confusion even among medical personnel is because if the HbA1c value is close to 5, then it is virtually identical in numerical value to mmol glucose in blood plasma. But, again it's a coincidence!

This discussion got me to thinking about where the conversion factors come from.

Going from mmolar (mmol/L) glucose in blood plasma to mg/dl glucose in blood plasma is just a simple units conversion problem from high school chemistry. (BTW, the use of mmol is somewhat sloppy terminology by the medical community because it technically should be mM or mmol/L.) Take the mmol/L value, multiply by the molecular weight of glucose (180.0 g/mol) to convert mmol to mg, and divide by 10 to convert L to dL. 180/10 is where the 18.0 comes from.

However, converting from % hemoglobin in blood that is glucosylated to mmol glucose in blood plasma is much more complicated. The calculation would involve (among other things) Avogadro's number, the molecular weights of hemoglobin and of glucose, the density of blood, and the weight percentage of hemoglobin (unglucosylated) in blood. I don't know what some of those values are, so I'll just trust that the equation Plasma Blood Glucose = (HbA1c * 35.6) - 77.3 was obtained correctly by someone who knows what they're doing. :)

c6h6o3
Sun, Jul-13-03, 17:41
Plasma Blood Glucose = (HbA1c * 35.6) - 77.3 was obtained correctly by someone who knows what they're doing. :)

That would give me an average around 83 mg/dl. (HbA1c of 4.5%). No way. My meter's average is 93.

Sherrielee
Sun, Jul-13-03, 18:43
c6h6o3 - Wow! How did you get your HbA1c down to 4.5?

What is your typical daily menu and exercise? (I might want to be a copycat".

Congratulations on the GREAT blood work!

rainne
Sun, Jul-13-03, 18:51
That would give me an average around 83 mg/dl. (HbA1c of 4.5%). No way. My meter's average is 93.


There's a good chart at this site:

http://www.geocities.com/diabeteschart/bloodsugarchart.html

And it agrees. A HbA1c of 4.5% = 83.

Maybe your meter needs calibrating. Or perhaps your bg drops during the night to create a lower average. Or maybe by design or just habit you are more likely to test when it's high.

c6h6o3
Sun, Jul-13-03, 19:27
c6h6o3 - Wow! How did you get your HbA1c down to 4.5?

What is your typical daily menu and exercise? (I might want to be a copycat".

Congratulations on the GREAT blood work!

Thanks. I am blessed with an unusually conscientious physician who diagnosed me as diabetic when all others had admonished me to "lay off the doughnuts". My glucose tolerance test was 114 fasting and 142 postprandial.

This morning I had 4 or five pieces of bacon, a medallion of Canadian bacon and water to drink. For lunch I had a salad consisting of baby spinach, shredded red cabbage, grated asiago cheese and anchovies with capers. Dressing was Litehouse Parmesan Garlic. I had a glass of Pinot Grigio with the salad. For supper I had a porterhouse steak (approx. 1 lb. including the bone) and most of a bunch of steamed asparagus. I had sugar free cook and serve Jello pudding (chocolate) made with cream instead of milk for desert. Substituting 1/3 cup heavy whipping cream and 1-2/3 cups of water for the 2 cups of milk called for on the package reduces the carb count per serving from 6 to around 2 and there's no effect on the taste or texture. (It only works for chocolate, though. The vanilla will not "set" properly and ends up runny, even after you chill it.) I had a mug of decaf French Roast with heavy cream and stevia with the pudding. I refuse to give up fine coffee, no matter how bad for me it is. This is a fairly typical weekend day for me. During the week it's harder, especially finding low carb foods for lunch, but I manage. I eat a lot of chicken caesar salads with no croutons.

I married late in life, and learned how to cook very well. In my early thirties I devoured every cook book I could find by Craig Claiborne and Pierre Franey. It's given me the skills to invent things and keep my diet interesting so that I don't feel deprived. Low carbing is just about impossible if you don't cook.

I do curls and one-armed presses every day with a 20 lb. dumbell (Dr. B recommends 10 lbs.) for about 15 minutes. I should do situps or some kind of abdominal exercise, but just haven't found the time yet.

I called Dr. Bernstein's office looking for a recommendation as to a physician in my area espousing his methods. No luck there, but his assistant told me that my HgbA1c was the lowest they had heard of from any diabetic flying solo. I had to feel good about that. I told her to be sure to tell Dick Bernstein that I would still be eating bagels if it hadn't been for that book he wrote.

Jim

CarolynC
Sun, Jul-13-03, 21:02
That would give me an average around 83 mg/dl. (HbA1c of 4.5%). No way. My meter's average is 93.
4.5% is fabulous!

I agree with rainne that maybe your blood glucose levels drop during the night when meter readings aren't being taken. Mine are about 30 mg/dl lower at 3 AM than they are at 6 AM.

Still, 93 vs 83 is only 12% different and is within the range of accuracy of the home meters. Home glucose meters generally have an accuracy of only within +/- 20%. (In fact, according to Rick Mendosa's website, there are no FDA standards for the accuracy of these meters!) Like almost all analytical chemistry measurements, the lower the levels being measured, the lower the accuracy. A glucometer is going to be more accurate reading a sample that is 300 mg/dl than it is for 90 mg/dl.

Sherrielee
Sun, Jul-13-03, 22:09
Carolyn is right. In the brochure for my meter (Freestyle), it actually states that blood drawn from the vein will be 7% lower than blood glucose (meter testing). So, that would make it only a little off. 83....WOW!

Thanks for all the diet/exercise tips. I hope that mine will come down to a below 100 average after I get some of tbis weight off. I am eating much less than you, but still very healthy LC stuff. I am doing exercise (treadmill, crunches) the days I don't go to the gym.

This is all very trying...sometimes I get really depressed, then sometimes I feel lucky to have a managable problem and that Br Bernstein wrote that book!

pepsi max
Mon, Jul-14-03, 00:49
to c6h6o3, an hba1c of 4.5% is fabulous!it gives us all encouragement to try an improve our own .i didn,t think it was possible to get the results under 5% in diabetes.going to try harder now.

rainne
Mon, Jul-14-03, 07:26
"I'd Still Be Eating Bagels" should be the title of Berstein's new book.

c6h6o3
Mon, Jul-14-03, 12:47
Carolyn is right. In the brochure for my meter (Freestyle), it actually states that blood drawn from the vein will be 7% lower than blood glucose (meter testing).

Whenever I go to have an A1c, I take a reading with my Freestyle within 1 minute of Dr. Kern's drawing blood. The last time: her lab results showed 97 mg/dl and the Freestyle was 96 mg/dl. Close enough, I'd say.

Jim

Sherrielee
Mon, Jul-14-03, 13:37
No kidding! Close enough. That is sure good to know.

I was actually mentally subtracting that 7% when my BG was high (trying to make myself feel better).

I can't get into see the Endochronologist I was referred to until Oct 8th (the 1st day the group is accepting new patients). So, I am thinking of getting one of those at-home AbA1c tests for my own personal knowlege. I don't think taking the averages of meter readings will give it to me.

I know the Freestyle will do a 2-week average...I haven't given it a try yet. Maybe I will start that today!