Thyroid peroxidase antibodies are actually antibodies in the blood that fight against thyroid cells and are the preferred indicator for diagnosing autoimmune diseases of the thyroid gland. The presence of elevated thyroid peroxidase antibodies indicates a possible thyroid disorder, most commonly Hashimoto’s thyroiditis. Although elevated thyroid peroxidase antibodies are diagnostic for thyroid autoimmune disease, a single elevated thyroid peroxidase antibody is not conclusive. Further tests such as thyroglobulin antibodies, thyroid microsomal antibodies, thyroid ultrasound, and thyroid function are required to fully confirm the diagnosis. If the results of these tests are normal, then no special treatment is needed and regular review of thyroid hormone levels will be sufficient. However, if there is an increase in thyroid peroxidase antibodies along with abnormal thyroid function, then it is likely that the condition is caused by Hashimoto’s thyroiditis and needs to be treated promptly, otherwise it will have a significant impact on all aspects of the body. It is not necessarily caused by thyroid disease, but may be caused by other factors such as emotional stress or medication, but further tests must be done to rule it out.