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Updates on Celiac Disease Screening and Testing from the 2013 International Celiac Disease Symposium

It’s been a busy three weeks since I attended the 2013 International Celiac Disease Symposium (ICDS) in Chicago and I have dedicated only two posts to the symposium thus far (as I was reminded by my friend last night). So, here is some more information for you. This will be post #3 of about 9 or 10 total.

On the first day of the conference, Dr. Benjamin Lebwohl from Columbia gave a lecture entitled “The Correct Diagnostic Approach.” Some of his bullet points on the diagnosis of Celiac Disease included the following:

  • At the current time, most algorithms for diagnosis use both blood tests (serology) and a small bowel biopsy.
  • The TTG IgA antibody is the blood test that is the most sensitive and specific for Celiac Disease. If a patient has a selective IgA deficiency (occurs in about 3% of the population), the deamidated gliadin peptide IgG (DGP IgG) can be useful for screening. The DGP IgA antibody is also more sensitive than the TTG IgA antibody in children under the age of 2.
  • The Celiac antibody tests are imperfect. In approximately 10% of Celiac patients, at time of diagnosis the antibody tests will be negative (normal) but there is still damage seen on biopsy. If these patients had only blood tests performed, their cases of Celiac Disease would be missed.
  • All patients with Irritable Bowel Syndrome (IBS) should be tested for Celiac Disease.
  • It is not feasible to screen all people for Celiac Disease because the positive predictive value (PPV) of the Celiac tests is too low. PPV refers to the percentage of patients with a positive test result who actually have a disease. He stated that if all people were screened, 2/3 of people with abnormal Celiac antibodies would actually not have Celiac Disease (too many false positives) .
  • Lastly, he reminded us that it is crucial that 4 to 6 biopsies be taken during endoscopy, as the damage from Celiac Disease can be missed if too few biopsies are taken. There are many people walking around who have Celiac Disease but were told that their small bowel biopsies were normal because not enough biopsies were taken. If you are interested in reading more about this, I discussed this in a recent post.

Later in the day, Dr. Enzo Bravi from Europe discussed rapid “point of care” tests for Celiac Disease.  There are several tests on the market that require only a few drops of blood and can give results in 5 to 10 minutes.  Simtomax and Biocard are two examples that are used in Europe and other parts of the world.  All of the rapid tests look for some combination of antibodies (TTG IgA, total IgA, DGP IgA and IgG, etc).  There are hopes that these tests will be especially useful in pediatric populations and in developing countries.  Dr. Bravi is currently researching if these tests can be used to assess compliance with the GF diet in Celiac patients who are already GF.   He emphasized that these tests are not intended to be used for the final diagnosis of Celiac Disease.  For more on the Simtomax tests, please see link.  I had an opportunity to briefly speak with Dr. Bravi during one of the breaks and learned that none of these tests are FDA approved for use in the U.S.  If/when they are approved,  I would love to be able to use them in a clinical research study!

Session 4 of the ICDS focused on the pathology of Celiac Disease.  The speakers were Drs. Marsh, Hart, and Bhagat.  We were reminded that small intestinal (duodenal) tissue biopsies are graded from Marsh Type 0 (normal) to Type 3 (villous atrophy and destruction).  Types 1 and 2, the intermediate lesions, have infiltration of tissues with white blood cells, which is called intraepithelial lymphocytosis (IEL). Type 2 also includes tissue hyperplasia, or thickening.

Type 1 lesions, with IEL only, can be seen in IBS and other causes of malabsorption.  If a patient has a Marsh Type 1 lesion in the duodenum and positive TTG antibodies, the diagnosis is either Celiac Disease or Crohn’s Disease.  If anti-endomysial antibodies are present, it is Celiac Disease, and if they are absent, it is Crohn’s Disease.

There are several other diseases that can cause villous blunting that is similar to that seen in Celiac Disease.  They include the following:

  1. Olmesartan associated enteropathy
  2. Common variable immunodeficiency (CVID)
  3. Crohn’s Disease
  4. Giardia infection
  5. Tropical sprue
  6. Autoimmune enterocolitis

CVID, an immunodeficiency, has a mean age of diagnosis of 35.  Two thirds of patients with CVID have increased IEL +/- villous atrophy on their biopsies.  Celiac antibody tests are often negative.  Patients with CVID have no improvement on the gluten free diet. This is one of the biggest red flags that CVID is a possibility for a patient.  CVID needs to be ruled out in cases of refractory (non-responsive) Celiac Disease.

Olmesartan is a medication used for high blood pressure (hypertension) that is in a category of drugs called ACE inhibitors. It can cause duodenal damage that is almost identical to that seen in Celiac Disease. Colchicine is another drug that can cause similar bowel changes.

The speakers emphasized that in patients with refractory Celiac Disease (that do not respond to the gluten free diet), #1-6 need to be excluded.

More information from ICDS to come, including what to do for those with “potential” Celiac Disease and nutrional aspects of Celiac Disease.  Thank you for both reading and being patient with me!

For additional information from the conference, please check out recent posts from both The Savvy Celiac  and Pretty Little Celiac who were official ICDS bloggers.

6 thoughts on “Updates on Celiac Disease Screening and Testing from the 2013 International Celiac Disease Symposium

  1. Cherish

    “The Celiac antibody tests are imperfect. In approximately 10% of Celiac patients, at time of diagnosis the antibody tests will be negative (normal) but there is still damage seen on biopsy. If these patients had only blood tests performed, their cases of Celiac Disease would be missed.”

    That was me. I suspect part of it is that I didn’t gluten load because the doctor who first tested me didn’t tell me I needed to. I’m not a big grain eater to begin with, but I did consume soy sauce and had a piece of bread every once in a while. Enough to keep me sick but also an insufficient amount for a positive test. After that, I was trying to figure out what was making me sick, and I thought wheat was okay, so I started eating more bread and tried to figure out what other foods were doing it to me, obviously not having much luck narrowing things down. However, because I was eating more bread, it was pretty obvious to my new GI, once he gave me a pill cam, what was going on. Unfortunately, that was three years of gluten-loading in the meantime.

    1. Jess Post author

      Hi Cherish,
      Thanks for reading…it’s nice to know that at least one person is reading my posts. I actually like you so much that I will continue to post just for you!
      Did you have your antibodies checked again around the time of your scope? Just wondering that if your original false negative was from being wheat and grain light, if you actually had a measurable response the 2nd time around.
      It was actually a bit disheartening to hear some of the experts discuss this at the ICDS, as I had thought that the antibody tests were supposed to be good. You do make me wonder, though, if many of the false negatives are because people have already cut back on gluten at the time of testing. I was fortunate that I had my original blood tests within 2 weeks of going GF, so they were still sky high!
      Jess

  2. Pingback: ICDS 2013: The Celiac Iceberg Revisited | The Patient Celiac

  3. Vik

    Jess, did the docs say if/ how often we should get blood retested after going GF, after the initial diagnosis? I thought we are supposed to check it after awhile to make sure that we are indeed not getting gluten into the system? I never had the majorly dramatic outward celiac symptoms, so am hoping that scrupulous adherence to the GF diet for 8 months has improved levels, as I might not know otherwise. if this makes sense. So, are the docs saying that a recheck could be a false negative?

    1. Jess Post author

      Hi again Vik,
      The overall consensus seemed that repeat testing should be at the 3 to 6 month GF mark, and then annually. Negative antibody testing for you would mean that your body is healing and that you are not continuing to be exposed to gluten. The only time that it would cause a false negative would be if you never had antibody tests for celiac disease, went GF, and then wanted to find out if you have celiac disease once you are GF. The only way to have a retroactive diagnosis, currently, is to undergo a gluten challenge.
      Does this make sense?
      Jess

  4. Jane

    I know this is old, but I only tested 32 to the DGP IGA and had “marked focal” inflammation in my intestine (duodenitis) after a recent hospitalization, but no villi blunting. 6 biopsies were taken, but I am not sure from what parts of the small intestine This was on a gluten free diet though. However, I had done 6 weeks of eating gluten in prep for a biopsy last year after a mere 21 DGP IGA and the biopsy was totally negative. I am DQ2 positive.

    Is there another cause of a positive DGP IGA? I cannot find one online. But I did find a study saying there was a 24% false positive rate in their subjects utilizing this test. Makes me wonder if there is another cause, or if perhaps the DGP IGA can become positive a bit before the gut is attacked enough to show up on biopsy.

    I feel so queasy and light headed with upper stomach pain. It concerns me that I do not have a positive answer. After my 6 weeks on gluten last year, my left adrenal gland showed calcification from what they think was a bleed or infection and my thyroid became inflamed. So we are still working on those diagnoses as well.

    I have an appointment next month at the Cleveland Clinic but am not sure I will be able to go.

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