Re: HbA1c - last 4 weeks most impact

January 10, 2006

Somewhere I do have a paper that says the most recent weeks have the

greatest impact but can't find it just now.

However, here's a simple explanation.

Let's assume HbA1c tests are conducted every three months.

Every day some red blood cells are replaced, so there are always some red

blood cells that are 120 days old, some that are brand new, and many in

between. So, in the last couple of weeks you'll have very few old red blood

cells. and mainly newer ones.

The HbA1c assesses the percentage of red blood cells that have glucose

attached. So, if you splurge and eat more carbs during the last couple of

weeks of the 3 months - several times, and thus have several higher post

prandial BGs (so more glucose attached to your red blood cells). So your new

HbA1c will be higher than if the slpurge had occurred straight after your

last HbA1c.

Bea

January 10, 2006

At 07:26 PM 1/10/06, Bea Pullar wrote:

> So your new HbA1c will be higher than if the slpurge had occurred

> straight after your

>last HbA1c.

Yeah, right after the last A1C is the time to have that chocolate cake if

you're planning on it. 8-)

Now that I have access to a fast-acting insulin I *can* do that. I don't

feel one bit guility about being able to allow myself more carbs and I

don't see why there'd be any problem with " getting used " to to insulin use

when I needed it. It's a sort of thinking I can't quite relate to...if my

pancreas worked properly then if I ate a slice of pie there'd be an

increase in insulin production to cover it. Why is it suddenly a " sin " or

" cheating " if someone does that with an insulin shot? Now I personally

don't plan on eating lots of carby things every meal or every day but I'm

so happy that if the urge for some pasta hits I can have a decent amount of

it.

sky

January 10, 2006

I'm with you, Sky. Blood draw day has its own little ritual here. I

meet friends for lunch after I've hit the dr's office, and have a

planned dietary excursion. I'm due any day now, and this time I'm

thinking lasagna, which I've been craving for about three years now.

It's not cheating, it's a treat.

CarolR

Sky wrote:

> At 07:26 PM 1/10/06, Bea Pullar wrote:

>

>> So your new HbA1c will be higher than if the slpurge had occurred

>>straight after your

>>last HbA1c.

>

> Yeah, right after the last A1C is the time to have that chocolate cake if

> you're planning on it. 8-)

January 10, 2006

Not a problem unless you start gaining weight.

Vicki

Re: HbA1c - last 4 weeks most impact

> At 07:26 PM 1/10/06, Bea Pullar wrote:

>

>> So your new HbA1c will be higher than if the slpurge had occurred

>> straight after your

>>last HbA1c.

>

> Yeah, right after the last A1C is the time to have that chocolate cake

> if

> you're planning on it. 8-)

>

> Now that I have access to a fast-acting insulin I *can* do that. I

> don't

> feel one bit guility about being able to allow myself more carbs and I

> don't see why there'd be any problem with " getting used " to to insulin

> use

> when I needed it. It's a sort of thinking I can't quite relate to...if

> my

> pancreas worked properly then if I ate a slice of pie there'd be an

> increase in insulin production to cover it. Why is it suddenly a " sin "

> or

> " cheating " if someone does that with an insulin shot? Now I

> personally

> don't plan on eating lots of carby things every meal or every day but

> I'm

> so happy that if the urge for some pasta hits I can have a decent

> amount of

> it.

>

> sky

January 11, 2006

At 11:45 PM 1/10/06, Carol wrote:

>I'm with you, Sky. Blood draw day has its own little ritual here.

Darn! I forgot I was going to go get some blood drawn today and so I ate

breakfast. Well...have to do it tomorrow. It might help if I had a ritual

to remind me.

>I meet friends for lunch after I've hit the dr's office, and have a

>planned dietary excursion. I'm due any day now, and this time I'm

>thinking lasagna, which I've been craving for about three years now.

>It's not cheating, it's a treat.

Good eating!

sky

January 11, 2006

At 11:58 PM 1/10/06, whimsy2 wrote:

>Not a problem unless you start gaining weight.

Happily, that hasn't happened.

sky

January 11, 2006

I have my second A1c test the first week in Feb (really hoping this one is

within " normal " range as then my doc may try me off meds (which actually scares

me a little but that is another story) . . .

My question is they have me coming in at 1:00 p.m. and say not necessary to fast

but from Gretchen's book, I'm wondering if my results will be as good? Or

should I just eat very light that morning so my BS upon arrival is low?

Sandy

Re: HbA1c - last 4 weeks most impact

Yup, me too. On the days when I have my fasting blood drawn for lipid

panel (every 3 months, when I get my A1C) I make sure to get first

vampire appointment in the morning at 9 a.m. then I meet a friend and go

out for breakfast.

Vicki

January 11, 2006

Yup, me too. On the days when I have my fasting blood drawn for lipid

panel (every 3 months, when I get my A1C) I make sure to get first

vampire appointment in the morning at 9 a.m. then I meet a friend and go

out for breakfast.

Vicki

Re: HbA1c - last 4 weeks most impact

> I'm with you, Sky. Blood draw day has its own little ritual here. I

> meet friends for lunch after I've hit the dr's office, and have a

> planned dietary excursion. I'm due any day now, and this time I'm

> thinking lasagna, which I've been craving for about three years now.

> It's not cheating, it's a treat.

>

> CarolR

>

> Sky wrote:

>> At 07:26 PM 1/10/06, Bea Pullar wrote:

>>

>>> So your new HbA1c will be higher than if the slpurge had occurred

>>>straight after your

>>>last HbA1c.

>>

>> Yeah, right after the last A1C is the time to have that chocolate

>> cake if

>> you're planning on it. 8-)

>

January 11, 2006

It's a problem for me as I don't know how to begin to shoot for a large

indiscretion. That doesn't mean I don't have the occasional off-WOE splurge.

Like others, I plan a lunch treat after my A1c and lipids are drawn.

I'm lighter than when I began insulin. It's a myth, that people will

automatically gain on it. Food choces are what constitutes weight gain, IMNSHO.

From: whimsy2:

Not a problem unless you start gaining weight.

Vicki

January 11, 2006

Is the C-peptide the same as the GAD antibody? I did request the GAD antibody

from him just recently to be done at the same time as the A1c I already had

scheduled (haven't received an answer from him yet) but if he says yes, I should

reschedule to the first thing a.m. ? I guess he isn't doing a lipid panel but I

am sorta curious about it.

Sandy

Re: HbA1c - last 4 weeks most impact

The A1c is not done fasting so a 1 p.m. makes no difference. Eat whatever

you would normally eat. If, however, they are also doing a lipid panel

and/or a C-peptide at the same time, then they should have you scheduled

for early morning and you should fast.

Nora

January 11, 2006

At 09:21 AM 1/11/06, Sandy wrote:

>I have my second A1c test the first week in Feb (really hoping this one is

>within " normal " range as then my doc may try me off meds (which actually

>scares me a little but that is another story) . . .

>

>My question is they have me coming in at 1:00 p.m. and say not necessary

>to fast but from Gretchen's book, I'm wondering if my results will be as

>good? Or should I just eat very light that morning so my BS upon arrival

>is low?

Whether you eat that morning may affect your BG's that morning but not your

A1c.

When I go in for some sort of bloodwork that requires fasting, my BG's are

always high because of the dawn effect which causes them to rise until I

eat. I try to go as early as possible because of that, not because I'm

worried about that one morning's BG's having any effect on an A1c.

sky

January 11, 2006

At 09:22 AM 1/11/06, whimsy2 wrote:

>Yup, me too. On the days when I have my fasting blood drawn for lipid

>panel (every 3 months, when I get my A1C) I make sure to get first

>vampire appointment in the morning at 9 a.m. then I meet a friend and go

>out for breakfast.

I'm really happy that I don't have to make an appointment for my blood

tests. The Dr. just gives me the lap slip when I see him or her, notes on

it (or just tells me) when it should be done, and I go in to the local

hospital lab whenever I want to. Now I just need someone to meet for

breakfast....

sky

January 11, 2006

At 10:20 AM 1/11/06, D wrote:

>It's a problem for me as I don't know how to begin to shoot for a large

>indiscretion.

It's hard to do, and since in me, at least, the Humalog seems to work for

up to 3 hours, I'll tend to wait at least 2 before trying to correct, and

then I'll only do it if the numbers remain above 200. Then I'd probably

dose lower than I'd need to take it down to baseline. My goal would be to

just get it down below 140 and then wait and see where I end up. I've only

done that about two times.

sky

January 11, 2006

> Whether you eat that morning may affect your BG's that morning but not

your

> A1c.

They tell you it won't affect the A1c but depending on how they measure the

A1c and whether or not they let the blood sit around a long time before

testing it, it can affect it if your BG is high. Here's what I wrote in the

T2 book:

" What happens is this. When the BG level in the blood is high, the glucose

first fairly quickly (over a period of several hours) attaches itself to the

hemoglobin by a very labile bond (for scientists: it's a Schiff base). Some

people call this temporary compound pre-A1c. You may also see it referred to

as the aldimine form. This reaction occurs fairly rapidly, but if the BG

level then goes down again, the glucose can come off. It's like suddenly

having a high level of cash and quickly putting it into a bank. It's not a

permanent situation. When your cash level goes down, you take the money out

of the bank again.

" But if your BG levels stay high, the glucose doesn't come off the

hemoglobin molecule. In fact, it is slowly, over a period of several weeks,

converted (for scientists: by an Amadori rearrangement) to a second

compound, the hemoglobin A1c (you'll sometimes see this referred to as the

ketoamine form) that is measured in the tests. This reaction is also

reversible. It can revert to the pre-A1c again. But it takes a long time,

several weeks, to go from A1c back to pre-A1c, so for the purposes of the

testing, the A1c is pretty stable.

" However, because the first step in this process happens fairly quickly and

is a function of the current level of glucose in the blood, if your BG level

had been very good for several months but for the past 2 days you'd let it

get very high, you could have very high levels of pre-A1c, the stuff that

has " temporary glucose " that can come off again if your BG levels go low. If

the lab uses a test that measures both the temporary pre-A1c and the

permanent A1c, your results might reflect your control in the previous days

instead of over the past month or so.

" This is also a good reason to be fasting when you have the A1c test done,

even though the instructions for the test say that's not necessary. An

extremely high BG level could cause an increase in this temporary pre-A1c,

especially if the blood sat around for a long time before it was tested.

" Some labs control for this by doing a first step that removes the pre-A1c.

Others don't. In most cases it probably won't make much difference. But if

your results don't seem to reflect your home testing, this is yet-another

factor that you might want to consider. "

What I'd do with a 1 p.m. appointment for an A1c would be to have a normal

breakfast and maybe even a midmorning snack then hold off on lunch until

after the blood draw. I think it's only very high BGs that would cause

problems.

Gretchen

January 11, 2006