From the Guidelines
The most accurate antibody for evaluating celiac disease is IgA antitransglutaminase 2 (anti-tTG) antibody, as it offers high sensitivity and specificity for celiac disease diagnosis, making it the preferred initial screening test 1. This test has a sensitivity of around 95% and a specificity of around 98% for celiac disease diagnosis.
Key Points to Consider
- IgA antiendomysial antibody testing is also highly accurate but is more labor-intensive and operator-dependent as it requires immunofluorescence techniques.
- When ordering anti-tTG testing, it's essential to simultaneously check total IgA levels, as approximately 2-3% of celiac patients have IgA deficiency, which could lead to false-negative results 1.
- In IgA-deficient patients, IgG-based tests (IgG anti-tTG or IgG deamidated gliadin peptide antibodies) should be used instead.
- Antigliadin antibodies are now considered obsolete for celiac diagnosis due to lower accuracy.
- Antiparietal cell antibodies are not used for celiac disease diagnosis at all but rather for autoimmune gastritis and pernicious anemia.
- For proper diagnosis, positive serological testing should be followed by duodenal biopsy while the patient is on a gluten-containing diet to confirm the diagnosis before initiating a gluten-free diet 1.
Additional Considerations
- The diagnosis of celiac disease should be based on a combination of serological tests, including IgA anti-tTG and IgA antiendomysial antibodies, as well as duodenal biopsy 1.
- The patient's clinical presentation, medical history, and family history should also be taken into account when diagnosing celiac disease.
- It is crucial to follow the patient's response to a gluten-free diet and adjust the treatment plan accordingly.
Summary of Recommendations
- Use IgA anti-tTG as the initial screening test for celiac disease.
- Check total IgA levels simultaneously with anti-tTG testing.
- Use IgG-based tests in IgA-deficient patients.
- Perform duodenal biopsy to confirm the diagnosis after positive serological testing.
- Consider the patient's clinical presentation, medical history, and family history when diagnosing celiac disease.
From the Research
Antibody Accuracy for Celiac Disease Evaluation
The most accurate antibody for evaluating celiac disease can be determined by examining the sensitivity and specificity of various antibodies.
- IgA antiendomysial antibody and IgA antitransglutaminase 2 antibody are highly specific and sensitive for celiac disease diagnosis 2, 3, 4.
- Antigliadin antibody is also used but has lower sensitivity and specificity compared to IgA antiendomysial and IgA antitransglutaminase 2 antibodies 3, 5, 6.
- Antiparietal cell antibody is not typically used for celiac disease diagnosis and is more commonly associated with pernicious anemia.
Comparison of Antibody Sensitivity and Specificity
- IgA antitransglutaminase 2 antibody has been shown to have high sensitivity and specificity, especially when measured using second-generation ELISA tests or immunochemiluminescent assay 2.
- IgA antiendomysial antibody is also highly sensitive and specific, with a sensitivity of 87% and specificity of 100% in one study 3.
- The combination of IgA antigliadin and IgA antiendomysial antibodies can provide 100% sensitivity and 100% negative predictive value for celiac disease diagnosis 5.
Diagnostic Recommendations
- The use of IgA antiendomysial or IgA antitransglutaminase 2 antibody is recommended for the diagnosis of celiac disease due to their high sensitivity and specificity 2, 4.
- A diagnosis of celiac disease should always be confirmed by histological evaluation of multiple duodenal mucosa specimens, with serology used for follow-up controls 2.