Screening for Celiac Disease in an Asymptomatic First-Degree Relative
Order tissue transglutaminase IgA (tTG-IgA) test with total serum IgA levels now. First-degree relatives of patients with celiac disease have a 10-15% lifetime risk of developing the condition, making them a high-risk population that warrants serologic screening even when asymptomatic 1, 2.
Why Screening Is Indicated
- The American Gastroenterological Association specifically identifies first-degree relatives as a population requiring screening, regardless of symptoms 1, 2.
- This child's 10-15% lifetime risk substantially exceeds the general population risk of 0.3-1%, justifying proactive screening 3, 1.
- Early detection allows for intervention before symptoms or complications develop, including malabsorption, nutritional deficiencies, and associated autoimmune conditions 1.
Appropriate Testing Strategy
- Order tTG-IgA combined with total IgA measurement, which has a sensitivity of 90-96% and specificity greater than 95% 1, 2.
- Total IgA levels must be verified to rule out selective IgA deficiency, which occurs in 1-3% of celiac disease patients and could cause false-negative results 1, 2.
- If IgA deficiency is detected, switch to IgG-based tests (IgG tTG or IgG EMA) 1, 2.
Critical Pre-Testing Requirement
- The child must remain on a gluten-containing diet until all testing is complete 1, 2.
- Never start a gluten-free diet before completing the diagnostic workup, as this leads to false-negative serology and inconclusive biopsies 1.
Why Reassurance Alone Is Inadequate
- Current guidelines do not support simply reassuring parents without screening when a first-degree relative has celiac disease 1, 4.
- Normal growth and weight do not exclude celiac disease, as some children have "silent" presentations with no apparent symptoms 5.
- The American Gastroenterological Association explicitly recommends screening this population 1, 2.
Why Starting a Gluten-Free Diet Is Inappropriate
- A gluten-free diet should never be initiated without diagnostic confirmation, as it represents a significant dietary burden requiring lifelong adherence 1.
- Starting the diet prematurely would make future diagnostic testing unreliable and potentially require a prolonged gluten challenge (at least three slices of wheat bread daily for 1-3 months) 1.
- Biopsy confirmation is recommended, especially in asymptomatic children, before prescribing significant dietary changes 3, 1.
Parent Education Points
- Educate parents about symptoms that would warrant immediate re-evaluation: poor weight gain or growth failure, unexplained irritability or behavioral changes, diarrhea, bloating, abdominal pain, or signs of malabsorption 1, 4.
- If the child develops type 1 diabetes in the future, repeat screening would be indicated per American Diabetes Association guidelines 3, 4.