Repeating Anti-TTG Testing After 8 Years
Yes, there is utility in repeating anti-TTG testing if new symptoms have developed or if there are clinical indications suggesting celiac disease, as celiac disease can develop at any age even after previous negative testing. 1
When to Consider Repeat Testing
The decision to repeat anti-TTG testing should be based on specific clinical triggers rather than routine screening:
- New or persistent gastrointestinal symptoms such as chronic diarrhea, constipation, abdominal pain, or bloating warrant repeat testing 1
- Unexplained iron deficiency anemia is a strong indication for celiac serology, as approximately 5% of patients with IDA have celiac disease 1
- Extra-intestinal manifestations including dermatitis herpetiformis, unexplained fatigue, premature osteoporosis, or elevated liver enzymes should prompt retesting 1, 2
- Development of associated autoimmune conditions such as type 1 diabetes or autoimmune thyroid disease increases pre-test probability 3, 2
- Family history of celiac disease in first-degree relatives increases risk and may justify repeat testing 3, 2
Key Considerations About Celiac Disease Development
Celiac disease is strongly genetically dependent (HLA-DQ2/DQ8) but can manifest at any age, with a population prevalence of approximately 1%. 1 The disease may remain latent for years before becoming clinically apparent, meaning a negative test 8 years ago does not permanently exclude the diagnosis. 4
Testing Approach
If repeat testing is warranted:
- Ensure adequate gluten intake before testing—patients must be consuming gluten-containing foods (at least 10g daily, equivalent to 3 slices of wheat bread) for 6-8 weeks prior to testing to avoid false negatives 1, 2
- Order TG2-IgA as the primary test with total IgA level to rule out IgA deficiency, which occurs in 2-3% of celiac patients and can cause false negative results 1, 4
- Consider endomysial antibody (EMA) if TG2-IgA is positive, as EMA has excellent specificity (99.6%) for confirmation 3, 5
Important Caveats
Do not test if the patient is already avoiding gluten, as this significantly reduces test sensitivity and may lead to false negative results. 1 If the patient has already started a gluten-free diet, they would need to resume normal gluten intake for 1-3 months before accurate testing can be performed. 1
Screening asymptomatic patients without risk factors is not recommended, even with a remote negative test. 4 The testing should be symptom-driven or risk-factor based rather than time-based.
When NOT to Repeat Testing
If the patient remains completely asymptomatic, has no new risk factors, maintains normal nutritional parameters, and has no family history of celiac disease, routine repeat testing after 8 years is not indicated. 4 The previous negative result remains valid in the absence of new clinical concerns.