Correlation between Serum Levels of 3,3',5'-Triiodothyronine and Thyroid Hormones Measured by Liquid Chromatography-Tandem Mass Spectrometry and Immunoassay

• Published in: PloS one 2015-10, Vol.10 (10), p.e0138864-e0138864
• Main Authors: Sakai, Hiroyuki, Nagao, Hidenori, Sakurai, Mamoru, Okumura, Takako, Nagai, Yoshiyuki, Shikuma, Junpei, Ito, Rokuro, Imazu, Tetsuya, Miwa, Takashi, Odawara, Masato
• Format: Article
• Language: English
• Subjects: Blood Chemical Analysis - methods; Chromatography; Chromatography, Liquid - methods; Cleanup operations; Correlation; Correlation analysis; Correlation coefficient; Correlation coefficients; Diabetes; Endocrinology; Feasibility Studies; Female; Hormones; Humans; Immunoassay; Linear Models; Liquid chromatography; Male; Mass spectrometry; Mass spectroscopy; Measurement methods; Medical screening; Metabolism; Methods; Middle Aged; Quality control; Radioimmunoassay; Radioimmunoassay - methods; Reproducibility of Results; Scientific imaging; Serum levels; Spectroscopy; Statistical analysis; Statistical methods; Studies; Tandem Mass Spectrometry - methods; Thyroid; Thyroid gland; Thyroid hormones; Thyroxine; Thyroxine - blood; Triiodothyronine; Triiodothyronine - blood; Triiodothyronine, Reverse - blood
• ISSN: 1932-6203; 1932-6203
• DOI: 10.1371/journal.pone.0138864

For measuring serum 3,3',5'-triiodothyronine (rT3) levels, radioimmunoassay (RIA) has traditionally been used owing to the lack of other reliable methods; however, it has recently become difficult to perform. Meanwhile, liquid chromatography-tandem mass spectrometry (LC-MS/MS) has recently been attracting attention as a novel alternative method in clinical chemistry. To the best of our knowledge, there are no studies to date comparing results of the quantification of human serum rT3 between LC-MS/MS and RIA. We therefore examined the feasibility of LC-MS/MS as a novel alternative method for measuring serum rT3, thyroxine (T4), and 3,5,3'-triiodothyronine (T3) levels. Assay validation was performed by LC-MS/MS using quality control samples of rT3, T4, and T3 at 4 various concentrations which were prepared from reference compounds. Serum samples of 50 outpatients in our department were quantified both by LC-MS/MS and conventional immunoassay for rT3, T4, and T3. Correlation coefficients between the 2 measurement methods were statistically analyzed respectively. Matrix effects were not observed with our method. Intra-day and inter-day precisions were less than 10.8% and 9.6% for each analyte at each quality control level, respectively. Intra-day and inter-day accuracies were between 96.2% and 110%, and between 98.3% and 108.6%, respectively. The lower limit of quantification was 0.05 ng/mL. Strong correlations were observed between the 2 measurement methods (correlation coefficient, T4: 0.976, p < 0.001; T3: 0.912, p < 0.001; rT3: 0.928, p < 0.001). Our LC-MS/MS system requires no manual cleanup operation, and the process after application of a sample is fully automated; furthermore, it was found to be highly sensitive, and superior in both precision and accuracy. The correlation between the 2 methods over a wide range of concentrations was strong. LC-MS/MS is therefore expected to become a useful tool for clinical diagnosis and research.