Diagnostic Testing

The Gluten File


RESULTS: Twenty patients could be followed during GFD and all antibody titres fell sharply within 1 month after introduction of a GFD and continued to decline during the survey interval. Thirty days after beginning the diet only 58, 84, 74 and 53% of all patients had positive antibody levels of tTGrh, tTGgp, EmA and AGA respectively.

Antibody levels in adult patients with coeliac disease during gluten-free diet: a rapid initial decrease of clinical importance. PMID: 15554953

Are you scheduled for a biopsy? Are you eating gluten?
Any changes in your diet can affect the accuracy of your biopsy results. It is necessary for you to be eating gluten every day for at least 4-8 weeks before the procedure. If you are scheduled for a biopsy and are not eating gluten, talk to your doctor about what is necessary to obtain accurate results. If you have a biopsy and have eaten gluten only a short time before the test, you and your physician will not know if a negative test result is accurate or due to your diet.

University of Chicago Celiac Disease Center

Clearing you of Celiac Disease today does NOT clear you for life.

If you are symptomatic and/or have tested positive to any of the antibody tests but failed to show biopsy damage, insist on periodic retesting. It is not uncommon for someone to have a negative biopsy one year, but a positive biopsy a couple of years later. It is also not uncommon to have negative blood tests for several years, which turn positive at a later date. And of course, even with a negative celiac biopsy, gluten sensitivity may be the cause of your symptoms. Read on!

A complete gluten sensitivity /celiac panel includes the following blood tests:

    anti-gliadin (AGA), IgA and IgG
    (increased significance for neurological manifestion of gluten sens)

   anti-deamidated gliadin (DGP), IgA and IgG
   (more specific to celiac disease)

  anti-TG2 (TG2), IgA and IgG
   (if positive, very suggestive of celiac disease)

  total serum IgA
   (rules out
IgA deficiency)

Being used in research:

   anti-TG6  (TG6), IgA and IgG (for neurological manifestion)

   anti-TG3 (TG3), IgA and IgG  (for dermatitis herpetiformis)

* * * IMPORTANT about Anti-gliadin antibodies! * * *

A newer test, anti-deamidated gliadin, has been developed over the last several years and some labs are beginning to automatically substitute it instead of the original antigliadin antibody tests.  The newer test is more specific to "celiac disease / villous atrophy", which is not helpful when looking for gluten sensitivity manifesting in non-gut ways (like neurological disease or other autoimmune disease), or when there are gut symptoms that have not yet caused villous atrophy.  BE SURE your doctor orders the original antigliadin tests. DOUBLE CHECK that the right tests are ordered, and DOUBLE CHECK that the right tests were run. You want anti-gliadin IgA and anti-gliadin IgG, over anti-deamidated gliadin.... or all of them!

Our findings suggest that the serological profile of gluten-sensitive ataxia/neuropathy without intestinal involvement lacks the recognition of deamidated gliadin and tissue transglutaminase epitopes.
Serology of celiac disease in gluten-sensitive ataxia or neuropathy: Role of deamidated gliadin antibody.
PMID: 21056914  Nov 2010

Further explanation of the tests:

To save cost, the celiac panel is often reduced to a single test... the anti-tTG IgA. Insist on more thorough testing than this single screening test!

Total serum IgA should always be run to rule out a condition called IgA deficiency. The other IgA tests are not reliable measures in someone who does not make enough IgA. 

Many "experts" consider the original antigliadin test as optional and outdated. It is said that antigliadin antibodies are not specific to celiac disease, but they are often the first to show and are of increased significance for those who may have gluten sensitivity manifesting as neurological disease. You want it!

The anti-endomysial antibody test is very specific for villous atrophy, but it has been replaced by the newer anti-tTG test.  In a perfect world, anti-tTG and anti-endomysial will be in alignment, but in the real world sometimes one is positive and other not. 
A thorough doctor will run both. Reticulin antibodies have fallen out of favor even longer ago, but I do know of one person diagnosed with biopsy proven celiac disease who had only an isolated positive anti-reticulin antibody.