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Blood Sugar higher at 2 hours than 1?

O

Oxcat1

Newbie
Messages
4
Type of diabetes
Type 1
Hello,

I'm not yet diagnosed but undertook a glucose tolerance test last week. I haven't got the results back yet, but I did sneakily test on my own meter - and now I'm confused!

My fasting reading was 4.9. After the standard oral glucose test solution, my reading was 9.9 at 1 hour and 12.2 at 2hrs.

Is there any possible explanation for this? I can't understand why the 2 hour reading could be higher than the 1hour? Obviously no fat or anything to slow absorption.

Any ideas? Thanks again.
 
I'm no expert, but recall when I was first diagnosed that many forum regulars recommended testing your BG 2 hours after you eat something.

I think that is to allow time for the glucose from the food to enter the bloodstream.
 
That is more or less correct but the point was that one would have expected the glucose from the solution to be absorbed well before then (being a liquid, it will pass through the stomach much faster than solid food, and thus be absorbed faster as well). So explaining this is a non-trivial question.

However, blood sugar readings aren't completely determined by carbohydrates eaten - insulin and glucose are released as part of the response to eating food so there's any number of interacting factors that could have lead to this observation.
 
Hi,

The 2 hour reading is usually considered the most important one for an oral glucose tolerance test. However, I'd be inclined to wait for your doctors verdict before worrying too much about the readings you took. You can't rule out a problem with the accuracy of the fingerstick test, especially if you'd just been handling glucose.

Good luck.
 
Thanks so much. I know the actual results will be accurate as they took blood from a cannula, but yes, my finger could well have been dirty, particularly given I was trying to test myself sneakily without anyone seeing.

Are you able to give any ideas of what kinds of things could have interfered/interacted to produce this higher second reading, if it is genuine? Thanks
 
Even if your glucose monitor was totally accurate , and you know there was no contamination then it wouldn't give the same reading as the venous reading. Blood from capillaries is similar in glucose levels at fasting to venous blood but different ( a bit higher) after 'eating'.

If genuine it's what you would expect from someone with impaired glucose tolerance /diabetes. see fig 27 (scroll down and click on graph )
http://www.zuniv.net/physiology/book/chapter27.html
compare the green line (diabetes) with the purple (normal) and the thin blue (impaired glucose)
A short explanation is that the first phase of insulin is very strong in a non diabetic, it starts immediately and minimises the rise in glucose levels. There is then a second phase that enables glucose levels to return to normal in about 2 hours ( longer if the glucose was only absorbed slowly but then the peak would also be lower.)
If the first phase isn't working correctly then glucose won't stop rising and will keep rising to higher levels than in a non diabetic. This could be because there is either not enough insulin produced or because the cells are resistant so there is relatively not enough insulin ( ie possibly lots of insulin but still more needed to get the glucose into the cell) The second phase of insulin release when it kicks in has to deal with higher levels. It may eventually be able to reduce levels back to 'normal' but will take longer (for the same reasons, not enough insulin produced or relatively not enough because of resistance)
 
Right - I got my actual results today and they're nothing like my finger-prick results!

Fasting was 8 (!!), but then between doing my an fingerprint at home and this one there was a 2 hour gap in which I didn't eat anything but did take my morning tablets. Maybe some of them are sugar coated?

1 hour was 10.8, and 2 hours was 9.0.

All a bit confusing. So far just the numbers from the doctor's receptionist with no interpretation at all, so difficult to make sense.

Any ideas? Thanks for all previous suggestions.
 
Oxcat1 said:
Fasting was 8
1 hour was 10.8, and 2 hours was 9.0.
Any ideas? Thanks for all previous suggestions.
Click to expand...

http://en.wikipedia.org/wiki/Glucose_tolerance_test

By these criteria, your fasting is too high for "impared glucose tolerance" (should be less than 7mmol/l), but your 2 hour is a bit too low for Diabetes (should be greater than 11.1mmol/l).

I suppose it's all a bit arbitrary. Whether you call it "impared glucose tolerance" or "T2 diabetes" the treatment is the same...

Your GP will tell you for sure but, until then, welcome to the club!
 
Hi,

Well I had a quick chat with a GP from my surgery who confirmed that I was on the borderline between impaired glucose tolerance testing and diabetes.

However, he said he was sure things would improve wiht diet and exercise. The trouble is, I weigh less than 8 stone already! I've lost more than 10kg since this whole thing started, and really don't think I can afford to lose anymore.

He then said that things would undoubtedly improve when I came off steroids. Again, probably true, but I've been on steroids continuously for about 10 years now (since I was 21) due to pretty severe asthma, and there is no chance of coming off them in the near future.

So, all in all a bit odd. And I'm still left losing weight all the time! Oh well. Hopefully someone will sort me out eventually.
 
Hi Oxcat, when you say "steriods" I assume you are talking about prednisolone? If so diabetes is a well known side effect of long term prednisolone/corticosteroid use, if your blood glucose (bg) is creeping up now it will only get worse.

My own diabetes was caused through long term (3 years) steroid use and I was diagnosed with very high bg levels of 29 mmol/? and an HbA1c of 12.9% and put straight on insulin treatment which as bad as it sounds actually helped me to gain good control fairly quickly. I was lucky then that I was weaned off the prednisolone over the next 6 or 7 months and after a year was able to stop the insulin treatment, but I had been obese and managed to loose 4 stone as well so that may have had a bearing on the high numbers at diagnosis.

Good luck with your doctors visit and if you are at all concerned about your readings before the appointment you can always ring your local emergency doctor service Em Doc :thumbup:
 
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