The measurement of free thyroxine by isotope dilution tandem mass spectrometry

Soldin, Steven J.; Soukhova, Nadia; Janicic, Nataša; Jonklaas, Jacqueline; Soldin, Offie P.

doi:10.1016/j.cccn.2005.02.010

Cited by 109 publications

(125 citation statements)

References 19 publications

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“…There is good correlation of free T4 by equilibrium dialysis and free T4 by liquid chromatography-tandem mass spectrometry (LC-MS/MS). 48 In a comparison of the IA and LC-MS/MS method in 109 patients, the correlation between free T4 and TSH was quite poor for the IA method and substantially better for LC-MS/MS. 49 Indeed, when the TSH was above or below the normal range, the inverse log-linear Pearson correlation was 0.45 for IA and 0.84 for LC-MS/MS.…”

Section: Free Thyroxine (Free T4)mentioning

confidence: 95%

Biochemical Testing of the Thyroid: TSH is the Best and, Oftentimes, Only Test Needed – A Review for Primary Care

Sheehan

2016

Clin Med Res

130

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Disorders of thyroid function are common, and screening, diagnosis, and management are often performed by primary care providers. While management of significant biochemical abnormalities is reasonably straight forward, laboratory tests only slightly outside, or even within, the normal range are becoming more difficult to appropriately manage. A large part of this increasing difficulty in appropriate management is caused by patients requesting, and even demanding, certain tests or treatments that may not be indicated. Symptoms of thyroid dysfunction are non-specific and extremely prevalent in the general population. This, along with a growing body of information available to patients via the lay press and internet suggesting that traditional thyroid function testing is not reliable, has fostered some degree of patient mistrust. Increasingly, when a physician informs a patient that their thyroid is not the cause of their symptoms, the patient is dissatisfied and even angry. This review aims to clarify the interpretation of normal and mild abnormalities of thyroid function tests by describing pituitarythyroid physiology and through an in depth review of, arguably, the three most important biochemical tests of thyroid function: TSH, free T4, and anti-TPO antibodies. It is important for primary care providers to have an understanding of the shortcomings and proper interpretation of these tests to be better able to discuss thyroid function with their patients.

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Section: Free Thyroxine (Free T4)mentioning

confidence: 95%

Biochemical Testing of the Thyroid: TSH is the Best and, Oftentimes, Only Test Needed – A Review for Primary Care

Sheehan

2016

Clin Med Res

130

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“…Although TSH measurement is commonly accepted as reliable, it is not well defined and there is no reference measurement procedure available. However FT4 assay methods include equilibrium dialysis, ultrafiltration and LC MS/MS [4]. Therefore, the routine measurements of FT4 and TSH have some limitations and assay methods have poor correlation.…”

Section: Discussionmentioning

confidence: 99%

Comparison of four immunoassay analyzers for relationship between thyroid stimulating hormone (TSH) and free thyroxine (FT4)

et al. 2015

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Comparison of four immunoassay analyzers for relationship between thyroid stimulating hormone (TSH) and free thyroxine (FT4) [Dört immünolojik ölçüm cihazının tiroid stimüle edici hormon (TSH) ve serbest tiroksin (FT4) arasındaki ilişki yönünden karşılaştırılması] ABSTRACTObjective: There is an inverse log/linear relationship between TSH and FT4 due to the negative feedback of these hormones on the pituitary. The objective of our study was to compare this relationship of TSH and FT4 between four different immunoassay analyzers. Methods: In our study, four data sets obtained from the database of four different hospital laboratories each using only a single method of measurement was used to evaluate this relationship between TSH and FT4.These data sets with their assay methods include: 21. for DxI 800 Unicel, Modular E 170, Architect i2000sr and ADVIA Centaur XP, respectively. In our study, all immunoassay analyzers showed poor correlation in a concentration range of TSH between 1.0 to 10.0 uIU/mL and the inverse log/linear relationship was not observed. Inverse relationship between TSH and FT4 is the result of negative thyroid pituitary hypothalamic feedback mechanism and this relationship is important especially in the diagnosis and treatment of hypo and hyperthyroidism. In data sets obtained from four different immunoassay analyzers, poor and statistically different correlation was observed between analyzers at TSH values ranged from 1.0 to 10.0 uIU/mL compared with FT4. Conclusion: These variations between analyzers may affect the clinical decisions especially in the evaluation of subclinical hypothyroidism, clinicians and laboratory specialists should be aware of these situation.

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“…Vitamin D analysis by LC/MS/MS is widely used in the clinical laboratory today. Whereas immunoassays are unable to distinguish between 25-hydroxy vitamins D2 and D3, the LC/MS methodologies are able to measure these levels separately so the contribution of each to the total can be determined.The capability of measuring thyroid hormones by tandem MS was developed recently and this has overcome the issues associated with immunoassays [3]. Triple quadrupole MS/MS is the preferred methodology for toxicology screening and for toxic drug quantitation [4].…”

mentioning

confidence: 99%

“…The capability of measuring thyroid hormones by tandem MS was developed recently and this has overcome the issues associated with immunoassays [3]. Triple quadrupole MS/MS is the preferred methodology for toxicology screening and for toxic drug quantitation [4].…”

mentioning

confidence: 99%

Mass Spectrometry Applications in Clinical Diagnostics

Meng¹

2013

J Clin Exp Pathol

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Mass Spectrometry (MS) is an analytical technique used for determining the elemental composition of samples, quantifying the mass of particles and molecules, and elucidating the chemical structure of molecules. Various types of MS with high specificity, such as Liquid Chromatography (LC-MS), Gas Chromatography (GC-MS), and Matrix-Assisted Laser Desorption/Ionization/Time-Of-Flight (MALDI-TOF MS), are being increasingly valued and utilized as tools in clinical laboratories [1]. These MS techniques overcome the limitations of immunoassays and offer many advantages over earlier approaches.Clinical laboratories use the MS technology for disease screening, diagnosis of disease and metabolic disorders, monitoring of drug therapy, identifying drug toxicity and poisoning, and discovering new biomarkers. Therapeutic monitoring of immunosuppressant drugs using MS is well established. Limitations of immunoassays such as nonspecific binding of the antibody and cross-reactivity with metabolites that often result in overestimation have made the more accurate LC/MS/MS methodologies the assays of choice [2]. LC/ MS/MS has become the standard for assay of steroid hormones for diagnosis of endocrine disorders. Vitamin D analysis by LC/MS/MS is widely used in the clinical laboratory today. Whereas immunoassays are unable to distinguish between 25-hydroxy vitamins D2 and D3, the LC/MS methodologies are able to measure these levels separately so the contribution of each to the total can be determined.The capability of measuring thyroid hormones by tandem MS was developed recently and this has overcome the issues associated with immunoassays [3]. Triple quadrupole MS/MS is the preferred methodology for toxicology screening and for toxic drug quantitation [4]. In newborn and prenatal screening programs, electrospray tandem MS has made possible identification of inborn errors in metabolism or genetic defects so that preventive and medical intervention can be implemented promptly to relieve or treat the disease [5]. One of the new ways that MS technology is being used is in proteomics, for quantitative identification of small amounts of proteins or molecules in blood to serve as biomarkers. This has opened up the discovery of new tumor markers as a potentially promising area of application of MS [6]. The intensive research into metabolomics, the assessment of endogenous metabolites as new disease biomarkers, is another promising applications of MS, which has been demonstrated to be very well suited to discovery and clinical application of metabolite profiles [7]. Another area of increasing interest is the use of automated MALDI-TOF MS for rapid identification of microorganisms in clinical microbiology laboratories [8].Yet, there are still challenges in the clinical application of this technology, including sample preparation, online extraction, throughput, automation, laboratory information system interfacing, inter-instruments standardization and harmonization, and FDA regulation. With emerging technologies in MS, we expect to see more...

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The measurement of free thyroxine by isotope dilution tandem mass spectrometry

Cited by 109 publications

References 19 publications

Biochemical Testing of the Thyroid: TSH is the Best and, Oftentimes, Only Test Needed – A Review for Primary Care

Biochemical Testing of the Thyroid: TSH is the Best and, Oftentimes, Only Test Needed – A Review for Primary Care

Comparison of four immunoassay analyzers for relationship between thyroid stimulating hormone (TSH) and free thyroxine (FT4)

Mass Spectrometry Applications in Clinical Diagnostics

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