Repeat Glucose Tolerance Test...Not diabetic???

[SandraRN]

So I repeated my GTT today. I did one in December with results of 230, 274, and 135, it was a three hour. So I was diagnosed with Type 2 possible Type 1.5. I asked for a repeat because the janumet and metformin I was on was doing nothing expect dropping my sugars and making me feel like **** and I had an ear infection going on the first GTT. So my doc finally broke down and let me repeat it so here are today's results of my 5 hour test, which I only made it to 4 hours: fasting was 82, 201, 111, 80, and 68.

SOOOOO, what the heck now? That's a pretty normal test to me. I felt like **** at 68 so I stopped the test but I always had problems with hypoglycemia even before the diagnosis in December. I also got antibody testing and some other labs drawn this morning so I am curious to see what that will show. I dunno what to make of all of it so far. I guess it is possible that ear infection screwed it up that much the first time. Can't wait to see what my doc says...

[fgummett]

I guess my only question: is it normal for someone without some form or stage of D to spike to 201 mg/dl no matter how much sugar they eat :confused:

[SandraRN]

I was wondering the same thing. The only thing on the internet I can find is that the first two hours you should be less than 200, and I was 201. So I dunno either. The results are so different from the first time though so it's all weird....

[fgummett]

If you have not already done so, you might check out a site called Blood Sugar 101 which has discussions on what constitutes truly normal BG levels.

They also discuss the reasoning behind why the ADA sets its guideline levels so high... in short: because of insurance considerations they want to be sure that someone is Diabetic before pronouncing diagnosis... so that does not leave much fudge room for folks who are "on their way" to D... especially when the guidelines get interpreted by some Doctors who look at -- as you say -- 200 as a cutoff value... below that you are OK then at 201 all of a sudden you have D. I honestly don't believe that the body works like that.

[jillrapp]

Sandra,
I would still bet on diabetes. Especially with episodes of hypoglycemia - that may go towards either being the cause of, or a symptom of diabetes. I was hypoglycemic for years before diagnosis. And your reading at 201. If you are not full blown now, I think you're on your way. :(

[foxl]

Could be your BG's fluctuate, over time, but ... not like it is gonna go away completely.

At minimum I would expect the clinical term used to be "pre-diabetes."

[lilituc]

Were you taking the medication when you had the test done? I don't see the value of it if you were on diabetes medication.

[lorilei]

I agree with lilly above...were u on meds? also...the type 1.5 rollercoaster dictates that you will live a silly and confusing life the first few months of diagnosis...don't turn in your cap just yet...(sorry)

[patricia52]

Have you had an A1C? It will give you your average BG for the last 3 months. Good Luck.

[EeyoreButterfly]

Ummm, 201 is not normal. Any reading over 200 is considered the threshold for diagnosis of full blown diabetes. It sounds like what happened was you spiked up then had a reactive hypo. That happened to me during my OGTT. I had a two hour, highest I hit was 165. I went upstairs to the lab (my mom is a microbiologist at the hospital) to await the results. Half an hour later (so 2.5 hours in) I was at 45.

There is no way that the results of your test would point to not diabetic. At the very least it would show prediabetes, but the 201 makes me suspect full blown diabetes. If you are type 1.5 you could be in an extended honeymoon stage which might be why your sugars are all over the place.

[REDLAN]

So I repeated my GTT today. I did one in December with results of 230, 274, and 135, it was a three hour. So I was diagnosed with Type 2 possible Type 1.5. I asked for a repeat because the janumet and metformin I was on was doing nothing expect dropping my sugars and making me feel like **** and I had an ear infection going on the first GTT. So my doc finally broke down and let me repeat it so here are today's results of my 5 hour test, which I only made it to 4 hours: fasting was 82, 201, 111, 80, and 68.

SOOOOO, what the heck now? That's a pretty normal test to me. I felt like **** at 68 so I stopped the test but I always had problems with hypoglycemia even before the diagnosis in December. I also got antibody testing and some other labs drawn this morning so I am curious to see what that will show. I dunno what to make of all of it so far. I guess it is possible that ear infection screwed it up that much the first time. Can't wait to see what my doc says...

Yep an ear infection can quite easily screw up a GTT.

As asked by Frank - is it normal to get a 200 on ANY GTT? well this depends, and it stems from the fact that most people (including doctors) do not understand the issues behind tests...

The GTT is a very sensitive test - this means that if you really do have diabetes, it is very good at detecting it. However the GTT is not a very specific test - this means that it will show up people as having diabetes when they don't in fact have it.

So to summarise - the GTT will only miss a very small number of people who do have diabetes, but will also catch quite a number who don't have diabetes. which is why the WHO do not recommend it as a screening tool. It is good as a follow up tool for confirming a diagnosis in someone who is suspected of having diabetes.

Using the sensitivity/specificity of tests it is possible to calculate the probability of having a particular disease, when some tests come back positive and some come back negative - very few doctors have any idea how to do this however

so I'm afraid it is not as simple as you have a GTT of 200 after 2 hours therefore you have diabetes, borderline diabetes or even pre-diabetes. No test is ever definitive.

Can't wait to see what my doc says...

that's what I would go for :)

[livelong]

From what I know now after I was Dx’ed I would state eating a lower carb diet just in case. You may be Pre Diabetic and taking care of it now will help you down the road. Since I learned to eat correctly I feel so good and healthy now. One year ago when Diagnosis I was 30 lbs over weight could not keep up with my ski and bike riding partners. They would be waiting for me to catch up. I followed the meal plan and dropped the 30 lbs. Now I have to wait for the same people that were waiting for me. I would be tied at work and now I sleep 6 hours, wake up feeling good and am never tired at work.

Like many have said on this forum, Diabetes is a healthy Disease and I am living proof of that. The meal plan they present in Diabetes education is what everyone should eat anyway.

[EeyoreButterfly]

I have never heard of the OGTT having a false positive. I've always heard that it does not matter how many grams of carbs you have, if you hvae a normally functioning endocrine system you should not go above about 120, certainly not over 200. In fact, any reading over 200 is supposed to be the threshold for diabetes.

[genie86333]

Hi, I noticed in your signature it says you're on Metformin. Your post said you're having problems with it - have you stopped taking it? If so, how long before the re-test did you stop taking it (because it takes a long while to get out of your system) and if it's still in your system either because you recently stopped or you're still taking it, then the lower readings are most likely just because of the Met.

[REDLAN]

EeyoreButterfly wrote
I have never heard of the OGTT having a false positive. I've always heard that it does not matter how many grams of carbs you have, if you hvae a normally functioning endocrine system you should not go above about 120, certainly not over 200. In fact, any reading over 200 is supposed to be the threshold for diabetes.

I found this discussion here on the WHO website -

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If you go to page 11, the document talks about the bimodal distribution of plasma glucose - there's a nice graph, showing 2 peaks. Those within the second peak to the right are at a much higher risk of developing diabetes. By choosing a cutoff somewhere in the dip you can separate out the 2 populations.

The article then goes on to discuss the wide variation in cutoffs in different racial groups which range from as little as 9.1 mmol/l (163) up to 17.9 mmol/l (322) - which puts the cutoff of 11.1 (200) in perspective.

The reason you won't have heard of false positives for OGTT is because it is considered to be the gold standard test for diabetes. It is assumed to have a sensitivity of 100% and a specificity of 100%. Other tests such as plasma glucose and HBa1c are compared to it to work out their sensitivities and specificities.

There is however no such thing as a Gold Standard Test - no test is ever perfect. The normal Gold Standard Test in medicine is the post mortem. However post mortem have an error rate - they know this by comparing the results of repeated autopsies. OGTT certainly does not have a sensitivity and specificity of 100% - it is simply the most diagnostic test currently available.

With OGTT you can generate false positives by testing during an infection, by giving too much carbohydrate during the test for the person's body weight, and by using the wrong cutoff for a particular racial group.

Here is a study which compares OGTT cutoff's for different racial groups during pregnancy

[url=http://www.ncbi.nlm.nih.gov/pubmed/8459959?ordinalpos=27&itool=EntrezSystem2.PEntrez.Pubmed.Pubmed_ResultsP anel.Pubmed_DefaultReportPanel.Pubmed_RVDocSum]Racial differences in oral glucose screening test ...[Obstet Gynecol. 1993] - PubMed Result (http://whqlibdoc.who.int/publications/2006/9241594934_eng.pdf)

they conclude...

Race-specific glucose screening test thresholds should be used to ensure consistency in properly identifying gravidas at risk for gestational diabetes mellitus.

[REDLAN]

that pdf WHO link

http://whqlibdoc.who.int/publications/2006/9241594934_eng.pdf

[angelsbridges]

Sandra,

Did you ever hear back from your doctor?