Rosh Internal Medicine Boost Practice Exam

For a patient with symptoms exacerbated by pasta consumption, what is the best method to confirm the diagnosis of celiac disease?

1. 25-hydroxyvitamin D

2. Duodenal biopsy

3. HLA-DQ genotyping

4. Tissue transglutaminase IgA antibody

The correct answer is: Duodenal biopsy

To confirm the diagnosis of celiac disease, performing a duodenal biopsy is considered the gold standard. This biopsy allows for the direct histological examination of the intestinal mucosa, where characteristic changes associated with celiac disease can be identified. In patients with celiac disease, there are typically findings of villous atrophy, crypt hyperplasia, and increased intraepithelial lymphocytes. While other methods such as tissue transglutaminase IgA antibody testing serve as useful screening tools, they may produce false positives or negatives, especially in certain situations like simultaneous autoimmune disorders or IgA deficiencies. HLA-DQ genotyping can help assess genetic predisposition but does not provide confirmation of the disease itself. Therefore, the biopsy is essential because it offers definitive confirmation through direct visual and histological evidence of the intestinal damage caused by gluten in individuals with celiac disease.