Abstract Background Thyroid function tests (TFT) which usually include thyroid stimulating hormone (TSH), total triiodothyronine (TT3), and free thyroxine (FT4) are widely applied in clinical practice for screening, diagnosis monitoring of disease. We evaluated analytical performance TSH, TT3, FT4 using DxI800 (Beckman Coulter, USA) including comparison to Alinity I (Abbott, USA). Methods Preci...