Standardization of Free Thyroxine Measurements Allows the Adoption of a More Uniform Reference Interval.

Background: The IFCC Committee for Standardization of Thyroid Function Tests intended to standardize free thyroxine (FT) immunoassays. We developed a Système International d'Unités traceable conventional reference measurement procedure (RMP) based on equilibrium dialysis and mass spectrometry. We describe here the latest studies intended to recalibrate against the RMP and supply a proof of concept, which should allow continued standardization efforts.

Value Assignment of Vitamin D Metabolites in Vitamin D Standardization Program Serum Samples.

Assay variability has been cited as an obstacle to establishing optimal vitamin D exposure. As part of the Vitamin D Standardization Program (VDSP) effort to standardize the measurement of total 25-hydroxyvitamin D [25(OH)D], the value assignment of total 25(OH)D in 50 single-donor serum samples was performed using two isotope-dilution LC with tandem MS methods. Both methods are recognized as reference measurement procedures (RMPs) by the Joint Committee for Traceability in Laboratory Medicine.

Harmonization of Serum Thyroid-Stimulating Hormone Measurements Paves the Way for the Adoption of a More Uniform Reference Interval.

Background: The IFCC Committee for Standardization of Thyroid Function Tests developed a global harmonization approach for thyroid-stimulating hormone measurements. It is based on a multiassay method comparison study with clinical serum samples and target setting with a robust factor analysis method. Here we describe the Phase IV method comparison and reference interval (RI) studies conducted with the objective to recalibrate the participating assays and demonstrate the proof-of-concept.

Monitoring the stability of the standardization status of FT4 and TSH assays by use of daily outpatient medians and flagging frequencies.

Clinicians diagnose thyroid dysfunction based on TSH and FT4 testing. However, the current lack of comparability between assays limits the optimal use of laboratory data. The International Federation of Clinical Chemistry and Laboratory Medicine (IFCC) gave a mandate to the Committee for Standardization of Thyroid Function Tests (C-STFT) to resolve this limitation by standardization.

The Empower project - a new way of assessing and monitoring test comparability and stability.

Background: Manufacturers and laboratories might benefit from using a modern integrated tool for quality management/assurance. The tool should not be confounded by commutability issues and focus on the intrinsic analytical quality and comparability of assays as performed in routine laboratories. In addition, it should enable monitoring of long-term stability of performance, with the possibility to quasi "real-time" remedial action.