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

Abstract

(197 words)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. Recently, the Committee members and their partners felt ready to set the step towards the technical recalibration. However, before implementation, they were furthered by the Food and Drugs Administration (FDA) to develop a tool to assess the sustainability of the new calibration basis. C-STFT began to use 2 online applications, i.e., the "Percentiler"and "Flagger", with the intention to assess their utility for this purpose. The tools monitor the course of instrument-specific moving medians of outpatient results (Percentiler) and flagging rates (Flagger) from data of individual laboratories grouped by instrument/assay peer. They additionally document the mid-to long-term medians, hence, are quality indicators of stability of performance of both laboratories and peers/assays. Here, the first experiences built up in the pre-standardization phase are reported. They suggest the suitability of both applications to document the sustainability of the calibration basis in the post-standardization phase.4

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

“…It is our plan to assess stability by our Percentiler application described elsewhere (Ref. 36). The decision will also require that the concerned manufacturers transparently communicate on relevant assay changes.…”

“…Whether the 4 assays selected here will do the future target setting, will depend on their long-term stability. We will assess this by our Percentiler application described elsewhere (36). Also, collaboration with proficiency testing organizers using commutable samples will be important to provide surveillance of the continuing relationship among different assays.…”

Biochemistry of the menopause

“…Implementation of such assays should reduce the variability of results. 121,124,125 A range of 11 thyroid hormones and metabolites can be measured in one method combining protein denaturation, SPE and LC-MS/MS 126 that would only need 50 μ L of serum or plasma (tested in adult frog plasma only). This method could be applied to human samples to assess thyroid homeostasis.…”

Optimization and validation of patient‐based real‐time quality control procedure using moving average and average of normals with multi‐rules for TT3, TT4, FT3, FT3, and TSH on three analyzers

“…It was very helpful to reduce the influence of abnormal results on data, but it also increased the workload of laboratorian to screen specimens. The Committee for Standardization of Thyroid Function Tests (C‐STFT) 21 used 2 online applications, the “Percentiler” and “Flagger,” in which the medians of samples data were compared. In this research, we used the Box‐Plot method to exclude the outliers from the normal distribution transformed data.…”