The normal range of thyroid tpo antibodies, i.e. anti-thyroid peroxidase antibodies, is <60IU/ml, so 654IU/ml is considered high. Increased anti-thyroid peroxidase antibodies are mainly seen in autoimmune thyroid diseases, such as Hashimoto's thyroiditis patients may have high titers of anti-thyroid peroxidase antibodies, and Graves' disease patients may have elevated antibody titers. The exact type of condition needs to be determined by thyroid function, thyroid ultrasound, and medical examination. In addition, antithyroid peroxidase antibodies may be positive in patients with postpartum thyroiditis, atrophic thyroid, and some nodular goiter. In conclusion, antithyroid peroxidase antibodies as high as 654 IU/ml are recommended for further consultation in the endocrinology department.