• Guest - w'd love to know what you think about the forum! Take the 2025 Survey »

Still pondering metformin effect... and plasma v whole blood

M

markd

Well-Known Member
Messages
220
I've lost exactly 102 pounds (low carb and moderate exercise) now and my BMI is 23.4, still on 1 x 500mg Met per day.

I bumped into my GP while out walking in the woods recently, in passing, he asked my how my BG was going - when I replied that fasting was generally between 4.3 and 4.6 and that after meals peaked at no more than 4.8 he nearly fell off the cliff. Night readings typically 4.1 to 4.8

We walked on for a couple of miles and I was delighted that he had to ask me to slow down a bit as he was getting short of breath (and he has to be a decade younger than me). He knows I'm an engineer and so like to put numbers to things and suggested that I might like to try an OGTT, though I'm not due a visit for another 4 months or so. He suggested a DIY OGTT using 415mL of 'original' Lucozade - a practice I've seen mentioned generally and on other forums on the web. (tastes better than the official glop too)

I got round to giving it a bash this morning - fasting; 4.5, one hour (not an 'official' measure, but lots of diabetes sites seem keen on it); 7.0, two hours; 4.5

I'm rather looking forward to bumping into him again, since we frequent the same walks - he with his iPod, me with an overactive dog; I'll be sure to catch him if he stumbles again.

Anyway, several thoughts/questions:

Has 1x 500mg Met per day seriously skewed my impromptu test to too low a level, bearing in mind that my BMI is now normal and I gather that Met makes a bigger difference in those with a high BMI?

I was recently in the US and bought a cheap meter ($9-99 from Walgreen) to use while there. Now I'd read that a conversion factor of 18 applied between US and UK figures, but then I read about plasma-calibrated v whole blood calibrated.

My OneTouch UltraSmart is apparently plasma calibrated and there is a 12% difference between the two.

So, anyone know if the fasting reading of 75 on my temporary US meter should be entered into my logbook as 4.2 or 4.7?

I binned the meter before I flew home - just didn't want the hassle of going thru airports with sharp things.

This was the device:

http://www.walgreens.com/store/product. ... rod4199459
Mark
 
Hi Mark,

Why not use the "Contact Us" link at the bottom of the Walgreens web page to ask them whether their monitor records whole blood or plasma.
 
I have no idea as far as the readings go, but I just wanted to say BLOODY WELL DONE!!!! Both on your incredible weight loss and getting those number that low. Kudos!
 
Sorry Cugila, the Ultrasmart,and all modern onetouch meters ,is plasma calibrated (see page 12 of the pdf.) Like all meters they use whole blood from a capilliary but then use an algorithm to display the result as if the sample were from plasma
I am pretty certain that all new US meters are plasma callibrated (on US forums they are surprised to hear that some of those in Europe are still whole blood) so in theory the 2 results should be treated equally.
Having said that I have an accucheck whole blood calibrated meter in mg/dl and a one touch plasma clalibrated in mmol. I did a few experiments testing using the 2 meters and soon realised that (after conversion from mg to mmol) they consistantly give very similar results without taking the 12% into account so I don't bother to account for it anymore.

Incidently for accucheck machines the info about whether it is plasma or whole blood is with the strips not the meter!
 
Hi phoenix.

I hear what you say.
Can you let me see the pdf document you refer to please. Page 12 of the owners manual taken from the website does not mention anything about Plasma calibration and is to do with coding and control solutions ?

I need to clarify this for future reference. :?

Edited today @ 0935 hrs.
Have finally got answer from US about the meter which is being used. The documentation in the US is different to here for some reason. One of the Tech guys confirms what you say is correct. He couldn't explain why it doesn't say it on the US manuals ?
So phoenix, you are correct and I have updated the database to reflect this. Thank you. :D

Ken.
 
Hi Cugila,
You went to a lot of trouble!
Sorry, if I didn't make it clear, Its on 'your' pdf, I used the search tool, using the word plasma, its p12 of the pdf but p1 of the document (after the intro pages) .
 
viv1969 said:
I have no idea as far as the readings go, but I just wanted to say BLOODY WELL DONE!!!! Both on your incredible weight loss and getting those number that low. Kudos!
Click to expand...

Thanks muchly!

While I can't say losing over one third of my body weight was easy, neither did it turn out to be as hard as I'd feared!

Having seen various diabetes-related studies that say even 7-10% weightloss can substantially improve diabetes (or prevent progression from pre-D to D) I wonder if there are any studies reporting much more substantial weight loss.

When diagnosed, I was just barely over the limit into D from pre-D, so I guess it is possible that I was tested on a 'bad day' and I've won myself a few years respite as pre-D again, from fullblown D.

We shall see!
 
deadwood2 said:
markd said:
So, anyone know if the fasting reading of 75 on my temporary US meter should be entered into my logbook as 4.2 or 4.7?
Click to expand...

Every credit. I'd average and pass on..
Click to expand...

Yes, you are probably right, no point being obsessive about these things - just that inaccuracy offends my engineering soul...
 
cugila said:
Your One Touch Ultra Smart meter is NOT plasma calibrated. It is a whole blood meter. Here is a link to the Owners Manual with all the information.

http://www.lifescan.com/pdf/ultrasmart_ob.pdf

If you read under INTENDED USE at the beginning it clearly states 'Whole Blood.

Ken.
Click to expand...

Hmm, I'd been reading the info sheet that comes with the strips that say the meters are 'plasma-calibrated to allow easy comparison with laboratory methods', but yes, now that you post that, I see what you mean.

I assume a 'true' plasma system would filter out the red and white cells and measure that directly, rather than including a scaling factor between measuring whole blood and indicating plasma reading as these would seem to do.

Mark
 
cugila said:
Edited today @ 0935 hrs.
Have finally got answer from US about the meter which is being used. The documentation in the US is different to here for some reason. One of the Tech guys confirms what you say is correct. He couldn't explain why it doesn't say it on the US manuals ?
So phoenix, you are correct and I have updated the database to reflect this. Thank you. :D

Ken.
Click to expand...

Interesting indeed - I've occasionally been tempted to buy test strips in the US, as they can be cheaper I wonder if this would introduce any calibration issues in a UK meter?

Mark
 
markd said:
We walked on for a couple of miles and I was delighted that he had to ask me to slow down a bit as he was getting short of breath (and he has to be a decade younger than me)
Click to expand...

Hehe, definition of an alcoholic

"Someone who drinks more than their doctor"

You're doing brilliantly IMNSHO, you've presumably beaten the hell out of your insulin resistance and discovered how many carbs you can still produce insulin to cover, and by eating within your flight envelope you have normalised your BG and insulin levels. Hence the loss of weight and increase in fitness.

That's an astonishing improvement, you've lost an entire small person!
 
Back
Top