Abstract: Objective　To investigate the clinical application of determining serum antithyroid peroxidase antibody (TPOAb) in patients with autoimmune thyroid diseases. Methods　Serum TPOAb were measured by electrochemiluminescence immunoassay in 130 patients with Graves disease, 117 patients with Hashimoto′s thyroiditis, 43 patients with lymphocytic thyroiditis, 29 patients with subacute thyroiditis, 34 patients with thyroid goiter, 24 patients with thyroid differentiated cancer and 63 controls. The receiver operating characteristic (ROC) curve was calculated， and the concentrations of serum TPOAb and the positive rate were compared among the groups. Results　The area under the ROC curve was 0.867，the cutoff value was 33.51 IU/mL， and the sensitivity and specificity were 82% and 89% at this cut-off value. The concentrations and positive rate of TPOAb had statistical significance among the groups (H=170.203，P<0.05，χ2=236.593，P<0.05). The concentrations and positive rate of TPOAb had significant difference between the group of autoimmune thyroid diseases and the group of non-autoimmune thyroid diseases(P<0.002 4). However, it had no significant difference between the groups of autoimmune thyroid diseases (P>0.002 4). Conclusions　The determination of serum TPOAb has an important value for the diagnosis of autoimmune thyroid diseases.

Key words: Anti-thyroid peroxidase antibody, Autoimmune thyroid disease, Diagnosis