What are the implications of testing positive for celiac disease antibodies, specifically tissue transglutaminase (tTG) antibodies and endomysial (EMA) antibodies?

From the Guidelines

Testing positive for celiac disease antibodies, specifically tissue transglutaminase (tTG) antibodies and endomysial (EMA) antibodies, indicates a high likelihood of celiac disease, an autoimmune disorder triggered by gluten consumption, and requires a gluten-free diet for management and prevention of complications. The most important antibody tests for diagnosing celiac disease include tissue transglutaminase (tTG-IgA), endomysial antibodies (EMA-IgA), and deamidated gliadin peptide antibodies (DGP-IgA and DGP-IgG) 1. For accurate testing, patients should continue eating gluten-containing foods before the test, as eliminating gluten can cause false negative results. The tTG-IgA test is typically performed first due to its high sensitivity and specificity, with a sensitivity of around 98% and specificity of over 95% 1. Since about 2-3% of celiac patients have IgA deficiency, total IgA levels should be measured simultaneously, and if IgA deficiency is present, IgG-based tests like DGP-IgG should be used instead 1. Positive antibody results usually require confirmation with an intestinal biopsy for definitive diagnosis, although some guidelines suggest that biopsy may not be necessary in certain cases, such as in children with high antibody levels and positive HLA-DQ2 or HLA-DQ8 1. Regular monitoring of antibody levels can also help assess dietary compliance in diagnosed patients, as levels should decrease with strict gluten avoidance, with a decline in antibody levels being sufficient evidence for proper management 1. However, it is essential to note that serology alone is not an accurate diagnostic tool for assessing dietary adherence in celiac disease, and a combination of serological tests and clinical evaluation is recommended 1. In patients with celiac disease, a gluten-free diet is the only treatment, and regular follow-up is necessary to monitor adherence to the diet and prevent complications such as malabsorption, anemia, and osteoporosis 1.

Some key points to consider:

• Celiac disease is a chronic small intestinal immune-mediated enteropathy triggered by the ingestion of gluten, and testing positive for celiac disease antibodies indicates a high likelihood of the disease 1.
• The tTG-IgA test is the most sensitive and specific test for diagnosing celiac disease, but IgA deficiency should be considered, and IgG-based tests used if necessary 1.
• Positive antibody results usually require confirmation with an intestinal biopsy, although some guidelines suggest that biopsy may not be necessary in certain cases 1.
• Regular monitoring of antibody levels can help assess dietary compliance in diagnosed patients, but serology alone is not an accurate diagnostic tool for assessing dietary adherence in celiac disease 1.
• A gluten-free diet is the only treatment for celiac disease, and regular follow-up is necessary to monitor adherence to the diet and prevent complications 1.

Overall, testing positive for celiac disease antibodies requires a comprehensive approach to diagnosis and management, including serological testing, intestinal biopsy, and regular monitoring of antibody levels and dietary compliance.

From the Research

Implications of Testing Positive for Celiac Disease Antibodies

Testing positive for celiac disease antibodies, specifically tissue transglutaminase (tTG) antibodies and endomysial (EMA) antibodies, has several implications:

• A positive test result indicates an immune-mediated response to gluten, which can lead to intestinal damage and malabsorption of nutrients 2, 3
• The presence of tTG and EMA antibodies is a strong indicator of celiac disease, but a definitive diagnosis is typically made via biopsy of the small bowel showing villous atrophy 2, 4
• A gluten-free diet is the primary treatment for celiac disease, and patients may benefit from support groups and education on managing the condition 2, 4
• Failure to respond to a gluten-free diet may indicate refractory celiac disease, which requires treatment by a gastroenterologist 2
• Some studies suggest that herbal supplementation may improve symptoms and laboratory results in patients with celiac disease, but more research is needed to confirm these findings 5

Diagnostic Considerations

When interpreting test results, consider the following:

• Serological tests for celiac disease-specific antibodies, such as tTG and EMA, are recommended for initial screening 2, 3
• Genetic testing for human leukocyte antigen alleles DQ2 or DQ8 may be performed in select cases 2
• Point-of-care tests can efficiently screen for celiac disease and improve the diagnostic timeframe 4
• Biopsy of the small bowel is still considered the gold standard for diagnosis, but may be avoided in certain cases, such as in children with high tTG levels and positive EMA test results 2

Nutritional Considerations

Patients with celiac disease may be at risk for nutritional deficiencies, including:

• Lower intake of total energy, carbohydrates, fat, and saturated and monounsaturated fatty acids 6
• Higher intake of certain micronutrients, such as vitamin A and E, in patients with diagnosed celiac disease 6
• Increased risk of malabsorption and nutritional deficiencies if a gluten-free diet is not properly managed 2, 6