ABSTRACT
Measurements of thyroid stimulating hormone (TSH) and free thyroxine (fT4) are critical for the early detection of thyroid diseases and for monitoring treatment. The IFCC Committee for Standardization of Thyroid Function Tests (C-STFT) established reference systems for TSH harmonization and FT4 standardization, and is now working national partners on implementing these reference systems. These implementation activities include the maintenance of the reference systems, their use to standardize and harmonize assays, and educational activities to inform stakeholders about anticipated changes in measurement values as a result of standardization and harmonization. The IFCC C-STFT formed a network of reference laboratories for FT4 and is creating a new harmonization panel for TSH. The U.S. Centers for Disease Control and Prevention is a member of the reference laboratory network and is launching a formal standardization program for FT4. In Japan, national organizations successfully implemented TSH harmonization and established harmonized reference intervals for TSH. The C-STFT made available on its website research findings about potential concerns, communication needs and benefits of FT4 standardization and is assisting local organizations with communicating changes related to these standardization and harmonization efforts. Implementation of fT4 standardization and TSH harmonization is a complex, continuous task that requires collaboration with IVD manufacturers, laboratories, physicians and health care providers. C-STFT is working successfully with national organizations and local groups on improving FT4 and TSH measurements.
