How to test for Celiac Disease.

How do you know if you have an issue with gluten if you have any of the other diseases or complications?
One thing people do is a 21 day elimination diet. To do this, you need to eliminate wheat, rye, barley and I also suggest malt and oats from your diet for 14 days. At about 1 week, you are liable to feel like crap as the body detoxes. Then between, day 7 and 14, you are on the upswing. Then you begin to eat gluten items again. For a week moving toward 21 days, you will know how you are affected by gluten. Now oats may not be an gluten item but they are usually contaminated by wheat production so I throw them in. I eat some “certified gluten free oats” from Trader Joe's after being diagnosed and I was in bed for 3 days.
 
Let’s talk tests:
People with Celiac Disease who eat gluten have higher than normal levels of certain antibodies in their blood. These antibodies are produced by the immune system because it views gluten as a threat. You must be on a gluten-containing diet for antibody (blood) testing to be accurate. So if you go gluten free, feel better off gluten and then want to get blood tested, they are going to tell you to eat gluten for several week to raise the antibodies to get a more accurate result. Sounds daunting right? Keep eating something that you realized is making you not feel so go.

1. Tissue Transglutaminase Antibodies (tTG-IgA) – The tTG-IgA test will be positive in about 98% of patients with Celiac Disease who are on a gluten-containing diet. This is called the test’s sensitivity. Rare, but the same test will come back negative in people with Celiac Disease called a false negative antibody test result.

There is also a slight risk of a false positive test result, especially for people with associated autoimmune disorders like type 1 Diabetes, autoimmune liver disease, Hashimoto’s Thyroiditis, Psoriatic or Rheumatoid Arthritis, and heart failure, who do not have Celiac Disease.
If you still believe you have issues after testing negative or with a positive test, the gold standard is a biopsy of the small intestine which is the only way to absolutely diagnose Celiac Disease.

There are other antibody tests available to double-check for potential false positives or false negatives.

Another such tests are:
     2. Total serum IgA: This test is used to check for IgA deficiency, a condition associated with Celiac Disease that can cause a false                         negative tTG-IgA.  If you are IgA deficient, your doctor can order a DGP or tTG-IgG test.
     3. Deaminated gliadin peptide (DGP IgA and IgG): This test can be used to further screen for Celiac Disease in individuals with IgA                  deficiency or people who test negative for tTg antibodies.

Link to the Fact Sheet from University of Chicago Celiac Center.