The TPOAb test measures antibodies against thyroid peroxidase, an enzyme involved in thyroid hormone production. High levels of TPOAb are often associated with autoimmune thyroid disorders like Hashimoto’s thyroiditis, which can cause symptoms such as fatigue, weight gain, and cold intolerance, and Graves’ disease, which may present with symptoms like weight loss, heat intolerance, and rapid heart rate. This test is essential for diagnosing these conditions, monitoring their progression, and guiding treatment strategies.