ObjectiveTo investigate the significance of carbohydrate antigen 199 (CA199), alanine aminotransferase (ALT), gamma-glutamyl transferase (γ-GT) levels in the diagnosis of liver damage caused by hyperthyroidism. MethodA total of 106 patients confirmed to have hyperthyroid liver damage between February 2012 and February 2014 were selected to form the hyperthyroidism liver injury group (group A). Ninety-five hyperthyroidism patients without liver damage were regarded as the hyperthyroidism without liver injury group (group B). In the same period, 72 healthy subjects were designated to form the control group (group C). Automatic chemiluminescence detector was used to determine free triiodothyronine, free thyroid hormone and CA199, and automatic biochemical analyzer was adopted to measure the levels of γ-GT and ALT. Then we performed the statistical analysis. ResultsThe levels of serum CA199, γ-GT and ALT in group A were significantly higher than those in group B and group C, and the differences were statistically significant (P<0.05). CA199 and γ-GT levels in group B were significantly higher than those in group C (P<0.05). The area under the receiver operating characteristic curve for CA199, γ-GT, ALT was respectively 0.840, 0.895, and 0.818, the maximum Youden indexes were 0.593, 0.703, and 0.578, with the corresponding critical values 37.25 U/mL, 60.81 U/L, and 43.14 U/L, respectively. The parallel dectection of the three indexes improved Youden index to 0.763. ConclusionsCA199, γ-GT and ALT as diagnosis indexes of hyperthyroidism liver damage have good diagnostic value, and combined detection of the three indexes is more favorable for early diagnosis and prediction.