Simultaneous quantification of free triiodothyronine and free thyroxine by isotope dilution tandem mass spectrometry

Gu, Jinlou; Soldin, Offie P.; Soldin, Steven J.

doi:10.1016/j.clinbiochem.2007.08.007

Cited by 80 publications

(82 citation statements)

References 42 publications

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“…Ultrafiltration was performed at 37°C instead of the previously published 25°C (19 ). Switching from 25°C to 37°C increases FT 4 results by a factor of 1.5 (21 ).…”

Section: Evaluating the Relationship Between Ft 4 And Tshmentioning

confidence: 99%

Inverse Log-Linear Relationship between Thyroid-Stimulating Hormone and Free Thyroxine Measured by Direct Analog Immunoassay and Tandem Mass Spectrometry

et al. 2011

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BACKGROUND: Accurate measurement of free thyroxine (FT 4 ) is important for diagnosing and managing thyroid disorders. Most laboratories measure FT 4 by direct analogue immunoassay methods. The validity of these methods have recently been questioned. The inverse log-linear relationship between FT 4 and thyroidstimulating hormone (TSH) is well described and provides a physiological rationale on which to base an evaluation of FT 4 assays.

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“…Ultrafiltration was performed at 37°C instead of the previously published 25°C (19 ). Switching from 25°C to 37°C increases FT 4 results by a factor of 1.5 (21 ).…”

Section: Evaluating the Relationship Between Ft 4 And Tshmentioning

confidence: 99%

Inverse Log-Linear Relationship between Thyroid-Stimulating Hormone and Free Thyroxine Measured by Direct Analog Immunoassay and Tandem Mass Spectrometry

et al. 2011

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“…When properly validated, these assays are not only highly accurate and sensitive, but also have the capability of measuring hormones in relatively low concentrations (2,7,8). We have recently described the use of this assay to measure thyroid hormones (9)(10)(11)(12). LC-MS=MS is more specific than immunoassays for measurement of thyroid hormones, allowing for the accurate and precise quantification of these analytes.…”

Section: Introductionmentioning

confidence: 99%

“…This is particularly true when conditions such as extremes of protein binding or interfering heterophilic antibodies are present. LC-MS=MS may perform better in such circumstances (9,11), and certainly, in the case of free thyroxine (FT 4 ), it seems to agree better with the gold-standard equilibrium dialysis assay (10).…”

Section: Introductionmentioning

confidence: 99%

Tandem Mass Spectrometry as a Novel Tool for Elucidating Pituitary–Thyroid Relationships

Jonklaas

Soldin

2008

Thyroid

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Background: Our objective was to determine the performance of liquid chromatography-tandem mass spectrometry (LC-MS=MS) in documenting both group and individual relationships between thyroid hormone and thyroid-stimulating hormone (TSH) concentrations. Methods: This was a prospective analysis of 50 euthyroid patients undergoing thyroidectomy. Thyroxine (T 4 ), triiodothyronine (T 3 ), free T 4 (FT 4 ), and TSH levels were documented on two occasions before thyroidectomy. After thyroidectomy, patients were treated with levothyroxine (LT 4 ) to achieve either a normal or low serum TSH concentration. All laboratory evaluations were repeated twice while patients were taking LT 4 . Thyroid hormone concentrations were documented by both immunoassay and LC-MS=MS, and their relationship with TSH was studied both in the entire group and in individual patients pre-and postthyroidectomy. Results: FT 4 and total T 3 correlated better with the log-transformed TSH when measured by LC-MS=MS. Postthyroidectomy the closest correlation was between log TSH and FT 4 (r ¼ 0.86, p < 0.001). The next best correlation was between log TSH and total T 3 (r ¼ 0.71, p < 0.001). When all data points were combined, the slope of the relationship between log TSH and total T 3 was relatively blunted compared with the log TSH-FT 4 slope (slope À 0.39 vs. À 1.38; p < 0.001), perhaps suggesting autoregulation of T 3 in response to the altered conditions postthyroidectomy. Conclusion: LC-MS=MS is an excellent tool for documenting the known physiological phenomenon of a loglinear relationship between TSH and thyroid hormone concentrations. In a group of patients studied pre-and postthyroidectomy, both FT 4 and total T 3 measured by tandem mass spectrometry correlate well with TSH. However, T 3 correlates slightly less well and has a relatively blunted relationship with the log-transformed TSH. These paired data suggest that in LT 4 -replaced patients T 3 concentrations are held stable in the face of fluctuating T 4 concentrations.

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“…Recently there is an increasing number of reports on quantitative analysis of serum free thyroid hormones using isotope-dilution-liquid chromatography-mass spectrometry (5,11,27,28). The advantage of the techniques compared to immunoassays is the much lower cost and duration of analysis with comparable accuracy, sensitivity and reproducibility.…”

Section: Introductionmentioning

confidence: 99%

“…Recent works report decreased selectivity and (quantification) reliability of immunoassays of thyroid hormones not only in tissue, but also in serum samples and all of them propose an alternative method for quantification of thyroid hormones and their metabolites (5,6,10,11).…”

Section: Introductionmentioning

confidence: 99%

LC-MS Quantification of Thyroid Hormones, Their Metabolites, Amino Acids and Neurotransmitters in Liver Tissue

Zanov

Yotova

Klapa

2009

Biotechnology & Biotechnological Equipment

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Simultaneous quantification of free triiodothyronine and free thyroxine by isotope dilution tandem mass spectrometry

Cited by 80 publications

References 42 publications

Inverse Log-Linear Relationship between Thyroid-Stimulating Hormone and Free Thyroxine Measured by Direct Analog Immunoassay and Tandem Mass Spectrometry

Inverse Log-Linear Relationship between Thyroid-Stimulating Hormone and Free Thyroxine Measured by Direct Analog Immunoassay and Tandem Mass Spectrometry

Tandem Mass Spectrometry as a Novel Tool for Elucidating Pituitary–Thyroid Relationships

LC-MS Quantification of Thyroid Hormones, Their Metabolites, Amino Acids and Neurotransmitters in Liver Tissue

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