What is the most appropriate initial test to diagnose celiac disease (CD) in an 18-month-old child?

From the Guidelines

The most appropriate initial test to diagnose celiac disease in an 18-month-old child is the tissue transglutaminase IgA antibody (tTG-IgA) test, along with a total serum IgA level. This blood test is highly sensitive and specific for celiac disease and is recommended as the first-line screening tool in children with suspected celiac disease 1. The total IgA level is important to check simultaneously because IgA deficiency is more common in celiac disease patients, which could lead to false-negative antibody results. For an 18-month-old child, it's essential to ensure they have been consuming gluten-containing foods for at least several weeks before testing, as antibodies won't be present if the child is on a gluten-free diet.

Key Considerations

• The tTG-IgA test has a high sensitivity and specificity for celiac disease, making it an effective initial screening tool 1.
• IgA deficiency is more common in celiac disease patients, which could lead to false-negative antibody results, emphasizing the importance of checking total IgA levels simultaneously 1.
• If the tTG-IgA test is positive, the child should be referred to a pediatric gastroenterologist for further evaluation, which typically includes an endoscopy with small intestinal biopsies to confirm the diagnosis 1.

Additional Recommendations

• Ensure the child has been consuming gluten-containing foods for at least several weeks before testing 1.
• Consider combining TTG IgA testing with IgG- and IgA-deamidated gliadin peptides in younger children to improve sensitivity 1.

From the Research

Diagnosis of Celiac Disease in Children

To diagnose celiac disease (CD) in an 18-month-old child, the most appropriate initial test is the measurement of anti-tissue transglutaminase antibodies (anti-tTG) [ 2, 3 ].

Key Findings

• The European Society of Pediatric Gastroenterology Hepatology and Nutrition (ESPGHAN) suggests using anti-tTG as the initial approach to symptomatic subjects [ 2 ].
• Anti-tTG has been shown to be more sensitive and specific than other antibodies, such as anti-Deamidated Gliadin Peptides IgA and IgG, in diagnosing CD in children [ 2 ].
• A study found that an anti-tTG value of 115 AU/mL had 76% sensitivity and 100% specificity for diagnosing CD in children [ 4 ].

Testing for Celiac Disease

Some key points to consider when testing for CD in children include:

• Anti-tTG is a useful initial screening test for CD in children [ 2, 3 ].
• The sensitivity and specificity of anti-tTG may vary depending on the age of the child and the severity of the disease [ 3, 4 ].
• A duodenal biopsy is still the gold standard for diagnosing CD, but anti-tTG can be used as a non-invasive initial screening test [ 5, 6 ].

Important Considerations

• The diagnosis of CD should be based on a combination of clinical judgment, serological tests, and duodenal biopsy [ 4 ].
• The use of anti-tTG as an initial screening test can help identify children who are at risk of developing CD and require further evaluation [ 2 ].