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That is something I have never understood about this board. On the dozens of other boards I have read, only the most critical 5% or so of threads get pinned. Here every thread is pinned. Totally defeats the purpose and concept of pinning threads.
The specificities of these assays are not 100%. That means false positives are always a statistical possibility. No test, of anything, is perfect.
I've also read that AGA IgG can be high for conditions other than celiac disease. I read that in a journal article I found while browsing.
This link says IgG AGA found positive in 10% of "normals." Also says may not be reliable.
From an article by Joseph Murray:
Also in thjat link Dr. Kumar states: "If the tests are performed using well standardized tests with known positive and negative predictive values then you can make the statement that if the serological tests are negative celiac disease can virtually be ruled out. The problem is that some of these assays, especially the gliadin, can give you false positive results." and "In patients with selective IgA deficiency only the IgG antigliadin antibody may be present, however, this antibody is less specific. It means that the IgG-type antigliadin antibody may be present in otherwise normal individuals."
This notion that one positive test means 100% certainty of celiac disease is simply not true.
As someone who performs difficult measurements for a living (I'm an engineer in a high tech company) I can assure you that no test is perfect. I don't care what you are trying to measure, you can always screw it up.
As for the contention that a positive blood test means that you have celiac with 100% certainty, I refer you to this document on this very site: LINK
If this notion was actually true, then the Positive Predictive Value of the tests would be 100% across the board. It is not.
As for me, I had only one of 3 blood tests come up positive for celiac disease, and it was IgG AGA. According to the document linked above, the probability that I have celiac disease based on that test alone is between 42% and 76%.
Now this linked article says nothing about tTG. My tTG was normal. I have seen the specificity of tTG quoted to be in the 90% range, so based on that test alone, one could conclude that I don't have celiac disease with about a 90% probability. Which stat is correct? Don't know, it is a gray area.
If you are lucky, all the tests in the panel will be pegged at either the high end or the low end, and then you can state your conclusion with great confidence. But in a case like mine, one cannot conclude squat from the blood tests.
As for my challenge...thanks for asking. It has been about 2.5 weeks and I don't feel any different at all. Have not gotten sick or anything. BMs are the same as they were off gluten. Of course I know this does not mean anything. It will be interesting to see what the blood tests say in a few months. But if nothing else, I now know that eating gluten does not produce any symptoms for me directly.
What is the sensitivity and specificity of his tests? Until I see these stats, I don't trust any of it.
As far as I am concerned, the fact that there are nothing but testimonials on his site which say "thank you for telling me I have celiac" and none that say "thank you for showing me I don't have celiac disease" raises a huge red flag. I have the feeling that if I sent him 100 control samples from non-celiacs he would tell me that 99 of them test positive for celiac disease. I'd gladly pay the $$$ if I knew the results would be definitive, but I until I see an independent assessment of his methods there is no way I will pay for it.
And here is the other frustrating aspect of this. Kaiti gave a good list of the various blood tests. We know that each of these tests has an associated sensitivity and specificity. But what are these stats when the blood panel yields mixed results? If you are AG IgG positive and tTG negative, what is the sensivity/specificty for these COMBINED results???? You never see this addresed.
Moreover, depending on the doctor, some tests are far more meaningful. For example, here is a link to a Mayo clinic document on celiac disease:
They have an interesting diagnostic flowchart. Look at it.
According to this, if I am tTG negative, and not IgA deficient (both of which are true for me), not only do I not need to get an endoscopy, I would be immediately considered to NOT have celiac disease. End of story. It says nothing about what to do with me because I was AG IgG positive.
These are great questions. I was wondering the same thing myself. I'm trained as a physicist so I am always questioning the veracity of the stats I come across related to celiac disease.
This is the other one that bothers me: on the blood tests I want to know what the measurement error is. You cannot measure or quantify anything without the possibility of error, and this error can be estimated. In my initial bloodwork, I was high only for gliadin IgG, nothing else. Without even talking about specificity or sensitivity, I want to know what the +/- is on my score. If they tested me 100 times on the same day, what would be the spread in the measurements? How much does the particular technician influence the results? Or environmental factors? Etc.
I doubt I will ever see results of a study on the gauge capability of these things! It's too bad, because when someone gives me experimental numbers without some error, I know the numbers are significantly less meaningful. And for a biological system, where there are many, many confounding factors, it is even more of a crapshoot, in all likelihood.
It is because of the completely inconclusive results of my bloodwork and the fact that gluten-free diet has not done much to impact my symptoms that I am doing a (doctor prescribed) gluten challenge right now.
I just eat low lactose. Have not tried total elimination of dairy, that is possibly a future experiment.
I appreciate everyone's comments and concern. I understand that there may possibly be other issues with gluten beyond celiac disease. I also understand that I am taking a risk with the challenge, in the sense that there is some probability that I am doing damage to my body right now. This is not something I did on a spur of the moment, I understand the gamble, and I am willing to take it. I did not do this on my own, I have been working with a gastro before even considering it. And if my response to the diet or my initial diagnosis had any clarity at all, I would not be doing this.
But I am simply unwilling to walk around the rest of my life not having a clue as to whether or not I have this serious, serious disease.
Well, if I thought there was a really good chance that I would be miserable on gluten, I probably would say NO to the challenge.
But like I said before, my gluten-free diet coincided with an abrupt change to my milk intake. And I know milk makes me sick, as I have done a 'milk challenge' - now it is time to do the gluten challenge in the same way for the same reason.
It will be interesting to see where I am in a week, a month, 3 months, etc. It has been 24 hours since I had some bread and I have not felt anything yet.
Well, I agree, that the world would be a better place if all gluten grains disappeared overnight! celiac disease or no celiac disease, I'd feel that way, just because I know how tough being gluten-free is. And even if it turns out I am not celiac I also deeply care and understand celiacs and try to help them in any way I can.
But I would never force this diet on my family. My wife would proably leave me if I made such a demand, and rightly so. 99 out of 100 people can eat gluten, and I'm not going to ask any of them to stop.
My initial diagnosis was sketchy. Again, no GI doctor in his right mind would look at my case and say "oh yeah, you are most likely a celiac." Gluten is either going to cause intestinal damage in me, or it is not, and I am going to require that these guys get it figured out with more compelling accuracy than what they have supplied so far. I do not think it is that much to ask or expect.
Wife: The boys really want my homemade pancakes. Do you mind if I buy some flour?
Me: Don't you dare open a bag of flour in my kitchen and get that crap everywhere. What are you trying to do, shorten my lifespan?
Boys: Can we all go out for pizza to celebrate (something)?
Me: Sorry son, I am not going to take you on the bus-tour of baseball stadiums like we planned, because I won't be able to control where and what I will be eating.
Me: Who used my syrup? That is my syrup. What did you touch the bottle against?
Wife: I just washed the dishes.
Me: This glass doesn't look clean enough. What is that little mark on the bottom? What if it has gluten? I'm not drinking out of that.
2. The strain of not knowing what is wrong. If I don't have celiac disease, this diet is not doing me any good, and I may have some other issue that has not been addressed. I'm not content to spend another 6 months expecting a miracle form the gluten-free diet when the diagnosis was totally sketchy from the start.
3. The constant avoidance of lunch with coworkers, social events, etc., and yet not knowing if my avoidance of these things is even needed, because my diagnosis of celiac disease is not firm at all. It is a lot easier to make a sacrifice when it has been demonstrated clearly that the sacrifice is necessary. I will have no problems about being gluten-free if indeed I need to be. I can do it, I can handle it. But I refuse to make a sacrifice unless I am certain I have to do it.
I guess I would tend to agree with you guys, except that there are confounding factors in my case that make me think the challenge is a good idea:
1. My tTG has always been normal, even on gluten. Only IgG antigliadin was high initially, but IgA was not. Also I am not IgA deficient, that was checked. From numerous sites, I have read that AG IgG is least specific for celiac disease and can be elevated due to other GI problems.
2. My loose stools have not changed at all in 6 months gluten-free.
3. The D has disappeared, HOWEVER, on day 2 of my gluten-free diet I discovered I was lactose intolerant (because a big glass of milk sent me to the bathroom), and I cut it out then and there. So is my lack of D due to the gluten-free diet, or the lactose-free diet? 3 months later I tried drinking another glass of milk and it made me sick again.
4. I went back in my food jounal I kept for 5 months before going gluten-free and found a high correlation between my D and crampy days and my milk intake.
So I really have no indication that the gluten-free diet has made me feel better, and frankly, I am suspicious of the diagnosis by a GP who doesn't know SQUAT about celiac disease anyway. My lethargy and body aches have not changed one bit since going gluten-free. If I end up poisoning myself for 3 months in order to get this definitively nailed down, so be it - I cannot mentally handle the lifestyle of this diet without knowing with 100% certainty if I have the disease. If I have it, fine, I already know what it takes to be gluten-free, and I can do it, but I need to know conclusively. And not one single Gastroenterologist could look at all my sysmptoms and test results and DEFINITIVELY say "Yes, you have celiac disease with 99.9% certainty" Or even 80% certainty. My case is totally inconclusive, and I am tired of not knowing what is wrong with me.
As for Enterolab testing, I'd have to pay for that myself, and I cannot afford it. Also from everything I have read I am a little doubtful about the validity of their testing. This is just my personal opinion. I have never read anything about anyone getting negative results back from them. My gut feeling is that they will tell me I might have celiac disease whether I really have it or not. Just my personal opinion - but every one of their 'testimonials' on their site is basically a sales pitch for the wonders of a gluten-free diet. And the gluten-free diet certainly is a miracle worker, but only if you have celiac disease. I still have problems that have not been diagnosed yet. Hence my upcoming colonoscopy.