What initial investigation is recommended for suspected celiac disease?

In suspected cases of celiac disease, immunology tests are the recommended initial investigation. These tests focus on specific antibodies that may indicate an abnormal immune response to gluten, which is a key factor in celiac disease. The most commonly assessed antibodies include tissue transglutaminase antibodies (tTG-IgA) and endomysial antibodies (EMA), which are highly sensitive and specific for celiac disease.

Testing for these antibodies is crucial because a positive result can support the diagnosis and guide further management. If the antibody tests are positive, this typically leads to a confirmatory small intestine biopsy to assess for intestinal damage, which is a hallmark of celiac disease.

The other options, while useful in different contexts, are not the primary initial screening tests for celiac disease. An upper GI series investigates structural abnormalities of the upper gastrointestinal tract, a colon biopsy is more pertinent for conditions affecting the large intestine, and stool studies can help assess malabsorption but are less specific for diagnosing celiac disease. Hence, immunological testing is the best starting point for making a diagnosis of celiac disease.