Nadia Soukhova1, Offie P Soldin, Steven J Soldin. 1. Bioanalytical Core Laboratory, Georgetown Clinical Research Center, Georgetown University, Washington, DC 20007-2197, USA.
Abstract
BACKGROUND: The thyroid hormones thyroxine (T4) and 3,5,3'-triidothyronine (T3) are essential for regulating a number of biological processes, including growth, neurodevelopment, carbohydrate metabolism, oxygen consumption and protein synthesis. Immunoassays are the current methods for thyroid hormone measurement and suffer from a lack of specificity. Our objective was to simultaneously measure T4 and T3 using isotope dilution tandem mass spectrometry within a single run. To compare the results obtained by this MS/MS method with those obtained by an immunoassay procedure on the same samples (DPC Immulite for T3, Diagnostics Product, and Dade RxL Dimension for T4, Dade-Behring). METHODS: An API-3000 tandem mass spectrometer (SCIEX, Toronto, Canada) equipped with TurboIonSpray and Shimadzu HPLC system was used employing isotope dilution with deuterium-labeled internal standard (l-thyroxin-d2). The method requires 100 microl of serum and involves addition of internal standard, precipitation of proteins with methanol and injection of the supernatant onto a C-18 column. After washing, the switch valve is activated and T4 and T3 eluted using a methanol gradient. T4 and T3 by immunoassay were performed using the Dade RxL Dimension and the DPC Immulite, respectively. RESULTS AND CONCLUSIONS: An isotope dilution tandem mass spectrometry method for the simultaneous determination of total T4 and T3 in serum is described which is accurate, specific, precise (%CVs 3.5-9.0), simple and fast (<7 min).
BACKGROUND: The thyroid hormones thyroxine (T4) and 3,5,3'-triidothyronine (T3) are essential for regulating a number of biological processes, including growth, neurodevelopment, carbohydrate metabolism, oxygen consumption and protein synthesis. Immunoassays are the current methods for thyroid hormone measurement and suffer from a lack of specificity. Our objective was to simultaneously measure T4 and T3 using isotope dilution tandem mass spectrometry within a single run. To compare the results obtained by this MS/MS method with those obtained by an immunoassay procedure on the same samples (DPC Immulite for T3, Diagnostics Product, and Dade RxL Dimension for T4, Dade-Behring). METHODS: An API-3000 tandem mass spectrometer (SCIEX, Toronto, Canada) equipped with TurboIonSpray and Shimadzu HPLC system was used employing isotope dilution with deuterium-labeled internal standard (l-thyroxin-d2). The method requires 100 microl of serum and involves addition of internal standard, precipitation of proteins with methanol and injection of the supernatant onto a C-18 column. After washing, the switch valve is activated and T4 and T3 eluted using a methanol gradient. T4 and T3 by immunoassay were performed using the Dade RxL Dimension and the DPC Immulite, respectively. RESULTS AND CONCLUSIONS: An isotope dilution tandem mass spectrometry method for the simultaneous determination of total T4 and T3 in serum is described which is accurate, specific, precise (%CVs 3.5-9.0), simple and fast (<7 min).
Authors: P Beck-Peccoz; P B Romelli; M G Cattaneo; G Faglia; E L White; J W Barlow; J R Stockigt Journal: J Clin Endocrinol Metab Date: 1984-04 Impact factor: 5.958
Authors: Jacqueline Jonklaas; Antonio C Bianco; Andrew J Bauer; Kenneth D Burman; Anne R Cappola; Francesco S Celi; David S Cooper; Brian W Kim; Robin P Peeters; M Sara Rosenthal; Anna M Sawka Journal: Thyroid Date: 2014-12 Impact factor: 6.568