From the Guidelines
Diagnosing celiac disease requires a combination of blood tests and intestinal biopsies, with the most recent guidelines recommending serum analysis of anti-tissue transglutaminase antibodies (TG2Ab) as the first-line screening test, followed by duodenal biopsy to confirm the diagnosis 1.
Key Steps in Diagnosis
- Blood tests to check for specific antibodies, including tissue transglutaminase antibodies (tTG-IgA) and endomysial antibodies (EMA-IgA), which are typically elevated in people with celiac disease.
- Total serum IgA levels are also measured to ensure accurate interpretation of other antibody tests.
- If blood tests suggest celiac disease, the diagnosis must be confirmed with an endoscopic biopsy of the small intestine, where a gastroenterologist takes multiple small tissue samples to examine for damage to the intestinal villi.
- It's crucial to continue eating gluten before these tests, as eliminating gluten prematurely can lead to false-negative results.
- Typically, patients should consume gluten daily (equivalent to at least 1-2 slices of bread) for 6-8 weeks before testing.
- Genetic testing for HLA-DQ2 and HLA-DQ8 genes may also be performed, as their absence makes celiac disease highly unlikely.
Importance of Recent Guidelines
The most recent guidelines, such as those from the Nature Reviews Gastroenterology and Hepatology 1, emphasize the importance of a multi-step approach in diagnosing celiac disease, including serology and duodenal biopsy, to ensure accurate diagnosis and effective management.
Considerations for Accurate Diagnosis
- Patients with suspected celiac disease but negative results from serologic tests should have their total IgA level measured, and be tested for anti-tissue transglutaminase, IgA against deamidated gliadin peptide, and endomysial antibody (IgA) 1.
- Patients with villous atrophy and genetic risk factors for celiac disease must undergo endoscopic evaluation after 1–3 years on a gluten-free diet to evaluate improvements in villous atrophy 1.
Conclusion is not allowed, so the response is ended here.
From the Research
Diagnosis of Celiac Disease
To diagnose celiac disease, several tests and procedures can be used, including:
- Serum tests to measure the levels of certain antibodies, such as tissue transglutaminase (tTG) and endomysial antibodies (EMA) 2, 3, 4, 5, 6
- Intestinal biopsy to examine the small intestine for damage and inflammation 2, 3, 6
- Genetic testing to identify individuals who are at risk of developing celiac disease, although this is not a diagnostic test 3
Serum Tests
Serum tests are commonly used to screen for celiac disease, and they can be used to monitor patients on a gluten-free diet. The most commonly used serum tests are:
- tTG IgA assay: this test measures the level of antibodies against tissue transglutaminase in the blood 2, 4, 6
- EMA IgA assay: this test measures the level of antibodies against endomysial antibodies in the blood 2, 4, 5, 6
- Anti-tissue transglutaminase type 2 IgA antibodies: this test can be used as a confirmatory test in children with celiac disease 5
Intestinal Biopsy
An intestinal biopsy is a procedure in which a small sample of tissue is taken from the small intestine and examined for damage and inflammation. This test is considered the gold standard for diagnosing celiac disease 2, 3, 6.
- Villous atrophy: this is a condition in which the villi in the small intestine are damaged and flattened, leading to malabsorption of nutrients 2
- Marsh 3 lesion: this is a type of lesion that is characteristic of celiac disease, and it is defined by the presence of villous atrophy and crypt hyperplasia 2
Non-Biopsy Approach
A non-biopsy approach to diagnosing celiac disease has been proposed, which involves using serum tests to diagnose the disease without the need for an intestinal biopsy 3, 5. This approach is based on the use of high-positive anti-TG2 antibody levels and confirmatory serology tests, such as EMA or anti-tissue transglutaminase type 2 IgA antibodies 5.