Comparison on the consistency of Mindray and Siemens chemiluminescence analyzers for detecting FT3, FT4 and TSH in patients with hyper- and hypothyroidism

Abstract

Background: To examine the consistency of the Mindray and Siemens full-automatic chemiluminescence analyzers in detecting serum free triiodothyronine (FT3), free thyroxine (FT4) and thyroid stimulating hormone (TSH) in patients with hyper-or hypothyroidism.Methods: Included in this study were 164 new patients with abnormal thyroid function assessed at Nan Fang Hospital of Southern Medical University in 2021: 107 patients with hyperthyroidism and 57 with hypothyroidism. Additional 100 healthy individuals comprised the control group. Consistency of the FT3, FT4 and TSH results from the two systems in the different groups was analyzed by Kappa, linear correlation, regression, Bland-Altman and area under the receiver operating characteristic curve (AUC).Results: Compared with the control group, FT3 and FT4 levels were increased and TSH level was decreased in the hyperthyroid group (both P<0.05), whereas FT3 and FT4 levels were decreased and TSH level was increased in the hypothyroidism group (both P<0.05), suggesting that both test systems could provide references for relevant clinical evaluation. Kappa analysis showed high consistency of the two systems in detecting FT3, FT4 and TSH in both hyper-and hypothyroidism patients (mean Kappa value >0.7). In addition, there was a good linear correlation between the test results of the two systems (R 2 >0.90).Bland-Altman consistency analysis showed that most mean difference values were within the consistency limit (x±1.96s), indicating that the difference between the two systems was acceptable. AUC of FT3, FT4 and TSH detected by the two systems was higher than 0.80 in each group, showing no significant difference between them (both P>0.05), and the difference in sensitivity and specificity was within the acceptable range.Conclusions: Mindray and Siemens chemiluminescence analyzers are highly consistent in detecting FT3, FT4 and TSH in both hyper-and hypothyroidism patients.