How Is A False Negative Possible? (if It Looks Like A Duck...)

[Tim86]

You've heard the expression...if it looks like a duck, swims like a duck, and quacks like a duck, then it's a duck. But what if it looks like a duck, swims like a duck, but clucks like a chicken? It's still probably a duck, but why does it cluck?

I've read many examples on this website of people who were clearly positive for Celiac, based on their experiences with gluten-free diets, and sometimes biopsy results, but their blood test results were negative. Assuming they had been consuming sufficient amounts of gluten at the time of testing, then how is this possible? How could all of their blood results be "normal" even though other evidence proves they have Celiac? I just don't understand. Please be specific and objective. I'm not looking for emotional responses here. I'd like a somewhat scientific explanation, if possible.

[Generic]

I can't give a scientific explanation, but some people just don't make the antibodies. I am example of this and so is my dad. He has rhuematoid arthritis SP?. A-typical polymyalgia and most likely Celiac, too but doesn't show it on any blood work. Other than the fact that his bloodwork is negative he has all the symptoms/damage.

There a few people on here who can give a more scientific explanation.

[Korwyn]

You've heard the expression...if it looks like a duck, swims like a duck, and quacks like a duck, then it's a duck. But what if it looks like a duck, swims like a duck, but clucks like a chicken? It's still probably a duck, but why does it cluck?

I've read many examples on this website of people who were clearly positive for Celiac, based on their experiences with gluten-free diets, and sometimes biopsy results, but their blood test results were negative. Assuming they had been consuming sufficient amounts of gluten at the time of testing, then how is this possible? How could all of their blood results be "normal" even though other evidence proves they have Celiac? I just don't understand. Please be specific and objective. I'm not looking for emotional responses here. I'd like a somewhat scientific explanation, if possible.

It doesn't have anything to do necessarily with being IgA deficient, it is just that the blood tests have a low sensitivity (as compared to specificity). Some of the statistics I've seen are as high as 80%. My doctor told me that she has never seen a positive blood work up come back even with some people confirmed later through biopsy. There are a lot of reasons having to do with individual immune system function, diet, enviornmental chemistry, other physiologic and immunologic issues, and the labs themselves. To be blunt, some labs just seem to do crappy workups.

[Tim86]

Does anyone else have some ideas on this? I know there are a lot of smart people out there who could chime in!

[Jestgar]

The tests for Celiac are based on production of antibodies to a specific region of gluten. They take your blood, put it on a plate with these specific sequences stuck to it, and then wash off your blood to see what stuck. If your body made antibodies to a slightly different region of the protein, your antibodies won't stick to the plate, and you will test negative.

The tests are designed to pick up MOST people's response, they won't pick up all.

[Another Undiagnosed]

I am so confused right now. A little over a year ago my doctor suspected I had Celiac due to a host of digestive issues, so I had the biopsy and the blood test. I recall being told that the biopsy was normal, but the doctor wanted me to get the blood test anyway (which makes me question if the biopsy was TOTALLY normal). Well, the blood test came back negative.

Recently I've been having all sorts of weird neurological stuff going on: tingling, twiching, occasional tremors. I also have all the frequent digestive complaints that I'm sure you all can figure out without me going into detail. I'm going to a neuro soon to rule out Multiple Sclerosis, but I've also heard Celiac can cause similar symptoms. To add to my suspicion, someone in my immediate family was recently positively diagnosed with Celiac. Is there any chance that, even after a biopsy and a blood test, maybe I do in fact have it? I am sort of hoping it is the case because even though it is a tough thing to live with, in my case it beats the alternative. Thanks everyone.

[nasalady]

I am so confused right now. A little over a year ago my doctor suspected I had Celiac due to a host of digestive issues, so I had the biopsy and the blood test. I recall being told that the biopsy was normal, but the doctor wanted me to get the blood test anyway (which makes me question if the biopsy was TOTALLY normal). Well, the blood test came back negative.

Recently I've been having all sorts of weird neurological stuff going on: tingling, twiching, occasional tremors. I also have all the frequent digestive complaints that I'm sure you all can figure out without me going into detail. I'm going to a neuro soon to rule out Multiple Sclerosis, but I've also heard Celiac can cause similar symptoms. To add to my suspicion, someone in my immediate family was recently positively diagnosed with Celiac. Is there any chance that, even after a biopsy and a blood test, maybe I do in fact have it? I am sort of hoping it is the case because even though it is a tough thing to live with, in my case it beats the alternative. Thanks everyone.

I had all of the same neuro symptoms you describe along with the gastro symptoms as well. I went to a neurologist and had an MRI of the brain, which was negative. I began to suspect celiac disease was behind the neuro symptoms because I had run across references to celiac ataxia, etc., in my research.

False negatives are common in both bloodwork and biopsy, so it is definitely possible you do have celiac disease.

I tested negative to both blood work and biopsy for celiac, although I had a good reason for that: I was (still am) on very high doses of prednisone and Imuran (which suppress the immune system) because of my autoimmune hepatitis...my immune system is trying to kill my liver, among many other things. Of course, these drugs suppress the body's ability to make antibodies and allow villi to regenerate in those with celiac disease. However, I still managed to register a "3" (0-5 being "normal" range for that lab) for the presence of the celiac antibodies, despite the drugs.

You didn't say whether or not you have tried the gluten free diet; my response to the diet was dramatic! My frequent headaches, vertigo, hand tremors, peripheral neuropathy, gastric problems, etc. all virtually disappeared or at least diminished on the gluten free diet. That was enough for me! The only issues that I have which have not (yet) resolved on the gluten free diet are those associated with my fibromyalgia and rheumatoid arthritis.

Good luck with everything!

JoAnn

[nasalady]

I can't give a scientific explanation, but some people just don't make the antibodies. I am example of this and so is my dad. He has rhuematoid arthritis SP?. A-typical polymyalgia and most likely Celiac, too but doesn't show it on any blood work. Other than the fact that his bloodwork is negative he has all the symptoms/damage.

There a few people on here who can give a more scientific explanation.

As Jestgar explained in such helpful detail, some people make more exotic antibodies that just won't show up in the standard tests. I too am seronegative for RA, but you can see the damage on xrays and my fingers are starting to develop the classic nodules at the joints. Even though I'm on prednisone and Imuran...

[Amyleigh0007]

I used that exact same expression with my doctor on Monday!! I love it!

He admitted to me that he usually only will diagnose someone with Celiac disease if they have smooth villi. Even with a positive blood test. That is very dangerous and I told him so. He went to med school 30 years ago and that is what he was taught. Perhaps these old school doctors are the reason so many of us go undiagnosed or are diagnosed incorrectly.

[momxyz]

To add to the confusion, try searching the board for Fructose Malabsorption.

This entity was pointed out to me recently. It will cause many of the same symptoms that celiac or gluten intolerance do, but the mechanism by which it does so is different.

[nasalady]

To add to the confusion, try searching the board for Fructose Malabsorption.

This entity was pointed out to me recently. It will cause many of the same symptoms that celiac or gluten intolerance do, but the mechanism by which it does so is different.

Lyme Disease mimics celiac too. But you won't generally find the antibodies or the gene markers for celiac disease if it's Fructose Malabsorption or Lyme. And you won't have problems with other autoimmune diseases developing with the mimics either.

[elye]

Is there any chance that, even after a biopsy and a blood test, maybe I do in fact have it? I am sort of hoping it is the case because even though it is a tough thing to live with, in my case it beats the alternative.

My husband had all of the classic symptoms of gluten intolerance/celiac, and a brother who was diagnosed three years ago. DH had a negative blood panel and a negative biopsy. He sprung for the enterolab stool test, and lo and behold, there were the antibodies - - lots of them. As well, there was a great deal of fat in the stool, another strong indicator of malabsorption. He immediately went gluten-free, and all of his symptoms were gone within a couple of weeks. So I would say that yes, it is definitely possible to have a problem with gluten even though the gold standard tests are telling you otherwise.

[Generic]

Ok, I guess my dad and I make "exotic antibodies". Works for me.