Celiac Disease

Diagnosis

(to be performed in patients on a gluten-free diet)

In patients under 5 years of age 1

• Anti-Gliadin Antibodies (AGA) IgA (S > 90%; E > 85%)
• Anti-Gliadin Antibody (AGA) IgG (S > 90%; E > 88%)
• IgA Anti-Tissue Transglutaminase (tTG) Antibody (S > 91%; E > 99%)
• Anti-Tissue Transglutaminase (tTG) IgG (if IgA deficiency is suspected)

In patients over 5 years of age

• Anti-Tissue Transglutaminase (tTG) IgA (S > 91%; E > 99%)
• Tissue transglutaminase (tTG) IgG 2 (if IgA deficiency is suspected)

Monitoring

(to be performed in patients on a gluten-free diet)

• Tissue Transglutaminase (tTG) IgA Antibody (S > 91%; E > 99%)³
  or
• Anti-gliadin (AGA) IgA antibody (S > 90%; E > 85%)⁴

1. Seroconversion to tTG IgA generally occurs only after 4–5 years of age; therefore, AGA (IgA and IgG) testing should be performed. On the other hand, transiently elevated levels of tTG IgA may be found in pediatric patients without celiac disease, so these patients should be monitored.

2. The risk of celiac disease is approximately 10–20 times higher in patients with IgA deficiency than in the general population.

3. IgA anti-tissue transglutaminase (tTG) antibodies are very useful in monitoring treatment, in addition to their role in diagnosis. Their levels may normalize approximately 6–12 months after starting the diet. tTG levels do not correlate with the repair of the intestinal mucosa.

4. IgA anti-gliadin antibody (AGA) is useful for monitoring treatment. The fact that they can be found in healthy patients limits their diagnostic value. Levels may return to normal approximately 3 to 9 months after starting the diet. To monitor patients with IgA deficiency, IgG anti-gliadin antibodies (AGA) are recommended over IgG tTG.