From the Guidelines
The specificity of anti-Tissue Transglutaminase (anti-TTG) antibodies for celiac disease is approximately 87-98% [ 1 ], indicating a high degree of accuracy in diagnosing the condition.
Key Findings
- The specificity of anti-TTG antibodies varies depending on the population and threshold used, with higher specificity observed in adults (87.4-98.1%) [ 1 ] compared to children (70.2-93.8%) [ 1 ].
- The threshold for a positive result also affects specificity, with higher thresholds resulting in higher specificity [ 1 ].
- In clinical practice, a positive result is typically defined as an anti-TTG IgA titer greater than 15-20 U/mL [ 1 ], with higher titers correlating with increased likelihood of celiac disease.
Comparison with Other Diagnostic Markers
- The specificity of anti-TTG antibodies is higher than that of anti-gliadin antibodies, making them a more reliable diagnostic marker for celiac disease [ 1 ].
- Endomysial antibodies (EMA) have a higher specificity (99.6%) [ 1 ] compared to anti-TTG antibodies, but are often used as a secondary test following an initial positive IgA tTG test [ 1 ].
From the Research
Specificity of Anti-Tissue Transglutaminase (Anti-TTG) Antibodies
- The specificity of anti-TTG antibodies for celiac disease is high, with studies showing specificities of 98.02% for anti-tTG IgA 2 and 90.1% for anti-DGP IgG 2.
- The high specificity of anti-tTG IgA antibodies makes them a reliable marker for the diagnosis of celiac disease, especially in pediatric populations 3.
- In contrast, the utility of isolated positive tTG IgG results in diagnosing celiac disease is low, with a specificity of 3% in one study 4.
- The use of anti-tTG IgA antibodies as a serological marker for celiac disease has replaced endomysial antibodies due to their ease of use, high sensitivity, and high correlation with intestinal mucosal lesions 3.
- Point-of-care tests for simultaneous detection of anti-tTG IgA and anti-deamidated gliadin IgG antibodies have shown good diagnostic accuracy, with specificities comparable to reference standard methods 2.