Automation of thyroid screening: A critical comparison of four systems

We compared four fully automated systems (Boehringer ES700, Tosoh AIA1200, Bayer Immunol, Mitsui Quartus) using 50 routine sera that included both euthyroid and pathological (with various degrees of hyper- or hypothyroidism) samples. The comparisons among systems by linear regression analysis yielded contradicting results, especially for fT4. Using the reference values of fT4 and TSH recommended from the manufacturers, the systems agreed completely in classification of patients in 32 cases; three systems agreed in seven cases, and two systems agreed in 10 cases; in one case, they completely disagreed. The agreement among the four systems we studied was high and would allow their introduction and use for routine thyroid screening. Comparison tests among fully automated systems for fT4 and TSH should not be determined only by linear regression statistical method, but additional functional validations must be performed.