American Board of Internal Medicine (ABIM) Certification Practice Exam

What antibodies are indicative of Hashimoto's thyroiditis?

1. Anti-phospholipase A2 receptor

2. Anti-desmoglein

3. Anti-microsomal, Anti-thyroglobulin

4. Anti-basement membrane

The correct answer is: Anti-microsomal, Anti-thyroglobulin

Hashimoto's thyroiditis is an autoimmune condition characterized by the immune system attacking the thyroid gland, leading to hypothyroidism. The presence of specific antibodies is a key diagnostic marker for this condition. In Hashimoto's thyroiditis, the antibodies that are most commonly associated with the disease are anti-microsomal antibodies (also known as anti-thyroid peroxidase antibodies) and anti-thyroglobulin antibodies. Anti-microsomal antibodies target thyroid peroxidase, an enzyme crucial for the synthesis of thyroid hormones. Meanwhile, anti-thyroglobulin antibodies target thyroglobulin, a protein essential in the storage of thyroid hormones. The detection of these antibodies is significant as it helps confirm the diagnosis of Hashimoto's thyroiditis in patients who present with symptoms of thyroid dysfunction and may assist in monitoring the disease's progression. The presence of these specific antibodies is considered one of the hallmarks of the condition and correlates with the autoimmune thyroiditis mechanism. Other antibodies listed, such as anti-phospholipase A2 receptor, are associated with conditions like primary membranous nephropathy; anti-desmoglein antibodies are related to pemphigus vulgaris; and anti-basement membrane antibodies are typically