Free Thyroid Hormones in Serum by Direct Equilibrium Dialysis and Online Solid-Phase Extraction–Liquid Chromatography/Tandem Mass Spectrometry

Abstract

BACKGROUND:Measurements of free thyroxine (FT 4 ) and free triiodothyronine (FT 3 ) are important for the diagnosis and monitoring of thyroid diseases. Considerable differences among methods limit their clinical utility, however, and accurate methods are needed for various clinical specimens. We describe a direct equilibrium dialysis (ED)-liquid chromatography (LC)/ tandem mass spectrometry (MS/MS) method for FT 4 and FT 3 .

Body composition and metabolic parameters are associated with variation in thyroid hormone levels among euthyroid young men

“…The analytical performance of these immunoassays has been questioned and biases have been reported, e.g. secondary to changes in binding proteins (41). We cannot therefore exclude that the measured levels of free thyroid hormones in our study are not entirely independent from TBG.…”

Report of the IFCC Working Group for Standardization of Thyroid Function Tests; Part 2: Free Thyroxine and Free Triiodothyronine

“…In addition, 2 laboratories that offer FTH routine clinical services with ED-ID-LC-MS/MS were included (1 performed FT4 and FT3, the other only FT4) (23,24 ).…”

Principles and Applications of LC-MS/MS for the Quantitative Bioanalysis of Analytes in Various Biological Samples

“…In pharmaceutical industries and toxicology laboratories, LC-MS/MS is the method of choice for the development and the measurement of drugs (Maurer, 2007). For clinical chemical analyses LC-MS/MS is rapidly emerging and is applicable to a broad selection of compounds, especially for the diagnosis of aberrations within the endocrine system, such as biogenic amines (Chan et al, 2000;Kushnir et al, 2002;Lionetto et al, 2008;de Jong et al, 2009a), but also steroids (Soldin and Soldin, 2009), thyroid hormones (Yue et al, 2008), and vitamin D (Higashi et al, 2008). Furthermore LC-MS/MS enable the use of sophisticated sample pretreatment techniques and automation of the whole process by on-line coupling of the separate techniques.…”