Please use this identifier to cite or link to this item:
Title: Interconversion of plasma free thyroxine values from assay platforms with different reference intervals using linear transformation methods
Authors: Meng, Fanwen
Jonklaas, Jacqueline
Leow, Melvin Khee-Shing
Keywords: Science::Medicine
Issue Date: 2021
Source: Meng, F., Jonklaas, J., & Leow, M. K.-S. (2021). Interconversion of plasma free thyroxine values from assay platforms with different reference intervals using linear transformation methods. Biology, 10(1), 45-. doi:10.3390/biology10010045
Journal: Biology
Abstract: Clinicians often encounter thyroid function tests (TFT) comprising serum/plasma free thyroxine (FT4) and thyroid stimulating hormone (TSH) measured using different assay platforms during the course of follow-up evaluations which complicates reliable comparison and interpretation of TFT changes. Although interconversion between concentration units is straightforward, the validity of interconversion of FT4/TSH values from one assay platform to another with different reference intervals remains questionable. This study aims to establish an accurate and reliable methodology of interconverting FT4 by any laboratory to an equivalent FT4 value scaled to a reference range of interest via linear transformation methods. As a proof-of-concept, FT4 was simultaneously assayed by direct analog immunoassay, tandem mass spectrometry and equilibrium dialysis. Both linear and piecewise linear transformations proved relatively accurate for FT4 inter-scale conversion. Linear transformation performs better when FT4 are converted from a more accurate to a less accurate assay platform. The converse is true, whereby piecewise linear transformation is superior to linear transformation when converting values from a less accurate method to a more robust assay platform. Such transformations can potentially apply to other biochemical analytes scale conversions, including TSH. This aids interpretation of TFT trends while monitoring the treatment of patients with thyroid disorders.
ISSN: 2079-7737
DOI: 10.3390/biology10010045
Rights: © 2021 The Author(s). This article is an open access article distributed under the terms and conditions of the Creative Commons Attribution (CC BY) license (
Fulltext Permission: open
Fulltext Availability: With Fulltext
Appears in Collections:LKCMedicine Journal Articles

Files in This Item:
File Description SizeFormat 
biology-10-00045.pdf1.8 MBAdobe PDFView/Open

Page view(s)

Updated on Jan 21, 2022


Updated on Jan 21, 2022

Google ScholarTM




Items in DR-NTU are protected by copyright, with all rights reserved, unless otherwise indicated.