Can anyone explain the Nutritional Information on this OGTT?

The sachet is for the Glucose Challenge Test, not the tolerance test.
https://www.ncbi.nlm.nih.gov/books/NBK279331/

Confirmed by the instructions requiring one blood test prior to drinking the solution followed by a single test at the 2hr mark. The tolerance test is longer duration and has several half hourly blood tests.

IncogKeto said:

Erm! What’s the forum etiquette when someone very kindly responds to your post but includes a link disproving their own comment?

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Errrm you respond by copying the relevant section of that link that suports a POV. You may disagree with that POV but the 50g Glucose dissolved in 300 ml liquid is the Challenge test requirement.
!"The glucose challenge test is the short version of the glucose tolerance test. The test can be done at any time of the day. It involves drinking a glass of concentrated glucose solution (50 g of glucose dissolved in 250 to 300 ml of water). After one hour has passed, a blood sample is taken to determine the blood sugar level."
I believed I answered the query as I understood it from the OP.

Oldvatr said:

Errrm you respond by copying the relevant section of that link that suports a POV. You may disagree with that POV but the 50g Glucose dissolved in 300 ml liquid is the Challenge test requirement.
!"The glucose challenge test is the short version of the glucose tolerance test. The test can be done at any time of the day. It involves drinking a glass of concentrated glucose solution (50 g of glucose dissolved in 250 to 300 ml of water). After one hour has passed, a blood sample is taken to determine the blood sugar level."
I believed I answered the query as I understood it from the OP.

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The correct etiquette is to query the comment where I stated a 2 hr mark test, which is indeed an error since the challenge test is at the 1 hr mark. the error is on the sachet since it states 2 hr mark as I quoted, but the challenge test is officially at the 1 hr mark. The Glucose Tolerance test is described in the section after the one I copied here, and is indeed a 75g glucose test so the sachet does not provide the correct dose for that (however it is diluted). The tests described in the link I provided is for diagnosing GD, but the full OGTT for T2D involves half hourly checks to get the full profile.

Actually, the Rapilose does give the impression it meets the requirements of the OGTT. The formal test is done using anhydrous glucose (i.e. unadulterated glucose) The sachet ingredients are glucose syrup, and glucose monohydrate both of which are diluted forms of glucose, so it seems that this describes the resultant compounds after dilution, and may have started out as anhydrous But neither carb nor sugar values gets to 75. But its the only arrow in their quiver, so there is only one OGTT as far as the manufacturers are concerned.

IncogKeto said:

Can anyone explain why the listed carbohydrate content was 71.5g and only 50.3g of that was sugars?

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Well I'm confused by this even if it is the challenge rather than the tolerance test. It says it has 75g of glucose on the front but only 71g in the fine print. I'd argue that the total carbs is relevant here but would have thought that glucose C6H12O6 counted as all sugar. (Glucose by definition is a simple sugar). 1g of glucose is 1g of sugar.

Why not phone or email the company to ask for clarification? (And report back here to tell us what they say).

Unless someone else here can clarify?

Just passing on something I noted in my research is that OGTT should not be applied to anyone taking beta blockers or diuretics, ot nicotinic acid. Also NO NO if you are using carb restricted diet (<150g) unless having a washout period of 3 days Eatwell prior to fasting. I would include VLC meal replacement shake diets in this warning too since they are effectively low carb too.
Not advised if your fasting level at the start is > 7.1 mmol/l

It seems that the test result tables tend to use Venous Blood Plasma values to support diagnostic testing in a hospital facility, so testing at home with a fingerprick tester may not correspond.

That's the real stuff alright, it's what surgeries use for their 75g OGTT.
It's what I used for my own home test

OK, How about this? The citric acid in the flavouring reacts with the glucose to form non sugar compounds such as invert sugar (i.e. the syrup) or fructose. So they count as carbs but no longer qualify as sugar in the strict labelling sense. So the manufacturers have partly altered the composition of their product by making it taste better.

Remember that the Krebs / Citric Cycle does this all the time in our bodies. Same process - acid reduction of glucose.

OK. It seems that the glucose powder sold by pharmacists is glucose monohydrate, and you need 82,5g for equivalence to the 75g anhydrous glucose of the test (according to data supplied by NHS on preparation for an OGTT) . Since Rapilose uses the monohydrate version, then the label does seem to indicate an incorrect amount of sugar.

This one seems to fit the bill
https://www.mistrymedical.com/item/...solution-250ml-bottle--box-of-24---msi337526-
Note the glucose content is correctly stated as 82.5g and the carbs and sugars agree.

However the carbs per 250 ml bottle works out at 70g, so again, either the carbs per 100ml seems to be in error or they are working on the 300 ml of the OGTT test definition but the smaller bottle will give an underdose.

IncogKeto said:

Hello there, and thanks for your replies.

I'm of a different opinion to you, believing that the test solution shown in my uploaded images is one that is used in a Tolerance test rather than a Challenge test.

It's stated on both the front and back of the sachet that it 'Delivers 75g of Glucose', which is the amount used in a Tolerance test - confirmed in the link you provided - whereas the Challenge test uses 50g of glucose.

The instructions on the sachet state that the patient should be in a fasted state and that the ideal test time is 9am which is consistent with the instructions in the link you provided for performing a Tolerance test - the Challenge test does not require these.

The instructions on the sachet also state that the second blood sample should be taken after 2hrs, which again is consistent with the instructions in the link you provided for performing a Tolerance test - the retest time for a Challenge test is 1hr.

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As I pointed out, the OGTT requires a specified amount. The sachet uses glucose monohydrate and should be providing 82.5g of sugar, but the label states only 50g. So either the nutrition info is incorrect,, or the actual dose administered is incorrect. I did show another supplier of OGTT test sample who showed the correct dose details, and correctly showed it as sugars. The Rapilose carbs total should also show 82.5g not the 71.5g

Just because someone gives a test methodology for the OGTT, does not make it correct. Just because a doctors surgery uses Rapilose for their OGTT again does not make it correct. The NHS data I mentioned is from the instructions for mixing the test sample with raw ingredients, and is from a textbook currently in use. They could use dextrose tablets instead but the required sample size required 80.9g of dextrose since it is 92% anhydrous glucose. For the Rapilose to be right, the carb content and sugars content should both be 82.5g

The authorised solution used within the NHS is either Fortical or Polycal supplied by Nutricia Care.

@Oldvatr man, take it up with the medical community not the OP
They used the correct solution full stop.
Don't twist yourselves in circles

There is good reason why I am being pedantic over this. The OP has correctly flagged up a problem with the information printed on the sachet and as viewed on the supplier website. The information on the pack is not compatible with the WHO OGTT 2hr test requirements. This is indeed a possible error in the labelling, and I have contacted tha manufacturer (Galen Ltd. Craigavon, NI) and their autoreply triage bot has registered my email. I await their response.

This site has seen many attempts by forum users trying to do their own OGTT test at home. The use of a premade solution for the OGTT would be a simple time saving step to take, so it is important that the solution is correct for purpose. If one is using an OGTT to provide evidence of full remission or of T2D diagnosis, then it becomes more important that the advice given here on the forum is valid.

For example, there was a study done by SAGE (the Gov.uk science body) in 1990 which compared the WHO glucose OGTT to one done using Fortical prepared solution. They took 55 non diabertic people and gave them a lab based OGTT first with one solution and then with the other after a washout recovery period. They used laboratory venous blood sampling and assay techniques.

They discovered that of the 55 participants several turned out to have a IGT or diabetic response, but the Fortical test passed 1 of them as normal who was then retested and confirmed to be diabetic. So in this admittantly small sample there was a 2% false negative result using the prepared solution rather than the official labmixed one. As a result the OGTT was deemed not capable of being used for diagnosis confirmation for T2D, but could be used for GD diagnosis. There was up to a 3 mmol/l difference between the two solutions at the 2 hr mark, and Fortical is one that definitely has 82,5g /300 ml glucose monohydrate.

So, forum users wanting to do their own OGTT now have access to at least 3 sources of premade solutions, and know that glucose bought OTC at the pharmacy is probably the monohydrate version so needs 82.5g not 75g. This is new information As an aside, dextrose tablets (91% carb) can also be used in solution but requires 82.4 g to be equivalent to the WHO standard.

I have been notified that a human at Galen is looking into this, and I will share their response when I get it.

Here is the response from Galen
"I believe the confusion may arise from not factoring in the conversion of the differing sugars contained in glucose syrup to anhydrous glucose equivalents on digestion.


Rapilose is specifically designed to deliver the equivalent of 75g of anhydrous glucose as per WHO 2hr OGTT guidelines.


Each 300ml solution pouch contains 86.4g of glucose syrup, which is a combination of simple and complex sugars, including mono-, di-, and tri-saccharides. However, on drying these produce a dry glucose amount of 71.5g per 300ml of liquid, which corresponds to the carbohydrate content that we quote in the pack nutritional information.


However, a further hydrolysis factor must be taken into account for each sugar type to show the conversion of these carbohydrates to anhydrous glucose (dextrose) equivalents on digestion. Applying these hydrolysis factors derives the requisite quantity of 75g of anhydrous glucose.

Additionally, given that all glucose syrups contain slightly differing ratios of sugars, each batch of Rapilose solution is further titrated using glucose monohydrate to cater for any small variations in the sugar content allowing us to deliver a precise total anhydrous glucose content of 75g ±1% per 300ml.

I trust this answers your question, however, should you require any additional information please do not hesitate to get in touch. Thank you for your interest in Rapilose OGTT.
Kind regards"

My comments:
di-saccharides are things like fructose, maltose, dextrose, lactose and galactose
tri-saccharides are triple compounds of glucose and fructose with galactose.called the oligosaccharides.
Question. does the use of syrup produce an insulin response comparable to that of dextrose alone. Does for instance fructose or galactose trigger a reaction at all when taken orally. It may do if used in an intravenous application like IVGTT which does not get require enzyme reaction from amylase, lactase or protase. I wonder what tests were done to verify this response.

Actually I found it, seems legit. Apparently this is the same evidence that Lucozade references in their attempt to offer their product for OGTT use.
https://pubmed.ncbi.nlm.nih.gov/13632059/