Antithyroid antibody studies are used to evaluate for autoimmune thyroid problems.
The reference ranges for antithyroid antibodies are as follows:
Thyroid peroxidase antibody (TPOAb): Less than 35 IU/mL
Thyroglobulin antibody (TgAb): Less than 20 IU/mL
Thyroid-stimulating immunoglobulin antibody (TSI): Less than 140% of basal activity
Thyroid-stimulating hormone (TSH) receptor binding inhibitor immunoglobulin (TBII)/TRAb: 1.75 IU/L or less