Free thyroxine measurement in clinical practice: how to optimize indications, analytical procedures, and interpretation criteria while waiting for global standardization

D’Aurizio, Federica; Kratzsch, Jürgen; Gruson, Damien; Ovčariček, Petra Petranović; Giovanella, Luca

doi:10.1080/10408363.2022.2121960

Cited by 10 publications

(4 citation statements)

References 256 publications

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“…However, the most common methods used for measuring free TH and TSH are chemiluminescent immunoassays. The results of both methods cannot be interchanged (D'Aurizio et al., 2023 ). It is therefore recommended to include measurements by the same methodology to compare the results and include sufficient details on the method used.…”

Section: Recommendationsmentioning

confidence: 99%

Specific effects on the thyroid relevant for performing a dietary cumulative risk assessment of pesticide residues: 2024 update

Crivellente,

Hernández‐Jerez,

Lanzoni

et al. 2024

EFS2

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EFSA updated its previous work on the establishment of specific effects that are considered relevant for grouping pesticide residues targeting the thyroid and for performing the retrospective assessment of dietary cumulative risk (CRA). The two specific effects already selected in 2019 leading to the two cumulative assessment groups (CAGs) 'hypothyroidism' and 'C-cell hypertrophy, hyperplasia and neoplasia' were reconfirmed. Compared to 2019, the list of indicators that can be used to identify these specific effects was refined to only include histopathological changes. In a second phase of the work, data will be extracted on indicators of the specific effects from the dossiers on active substances (a.s.) used as plant protection products. The criteria for including a.s. into CAGs were also updated, together with the hazard characterisation methodology and the lines of evidence for assessing CAG-membership probabilities. The tasks related to the data extraction and the establishment of the CAGs on hypothyroidism and on C-cell hypertrophy, hyperplasia and neoplasia are beyond the scope of this report. This part of the CRA process has been outsourced and will be the subject of a separate report.

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Section: Recommendationsmentioning

confidence: 99%

Specific effects on the thyroid relevant for performing a dietary cumulative risk assessment of pesticide residues: 2024 update

Crivellente,

Hernández‐Jerez,

Lanzoni

et al. 2024

EFS2

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“…Thyroid function can be accurately assessed by measuring TSH and free thyroid hormones (i.e., free thyroxine, FT4; free tri-iodo-thyronine, fT3). TSH and FT4 have a complex, non-linear, inverse relationship resulting in relatively large changes in TSH compared to small changes in FT4 concentrations, respectively [30][31][32]. Accordingly, except in some rare conditions (i.e., central hypothyroidism, resistance to thyroid hormones, TSH-secreting pituitary adenoma, hyperthyroidism under treatment, and euthyroid sick syndrome), TSH measurement is a sensitive and the most accurate test for thyroid dysfunction [33,34].…”

Section: Laboratory Medicinementioning

confidence: 99%

“…Accordingly, a thyroid scan is generally performed when nodules occur in people with low or low-tonormal TSH levels. The relationship between thyroid autonomy and TSH levels, however, is affected by the degree of iodine sufficiency and varies widely regionally [31,32,34]. Therefore, although autonomous nodules are almost invariably accompanied by decreased TSH levels (i.e., <0.1-0.4 mUI/L) when the iodine supply is adequate, the bulk of autonomous tissue may be insufficient to suppress the TSH level in iodine-depleted thyroids, especially in the early phases of autonomy.…”

Section: Nuclear Medicinementioning

confidence: 99%

Integrated Diagnostics of Thyroid Nodules

Giovanella,

Campennì,

Tuncel

et al. 2024

Cancers

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Thyroid nodules are common findings, particularly in iodine-deficient regions. Our paper aims to revise different diagnostic tools available in clinical thyroidology and propose their rational integration. We will elaborate on the pros and cons of thyroid ultrasound (US) and its scoring systems, thyroid scintigraphy, fine-needle aspiration cytology (FNAC), molecular imaging, and artificial intelligence (AI). Ultrasonographic scoring systems can help differentiate between benign and malignant nodules. Depending on the constellation or number of suspicious ultrasound features, a FNAC is recommended. However, hyperfunctioning thyroid nodules are presumed to exclude malignancy with a very high negative predictive value (NPV). Particularly in regions where iodine supply is low, most hyperfunctioning thyroid nodules are seen in patients with normal thyroid-stimulating hormone (TSH) levels. Thyroid scintigraphy is essential for the detection of these nodules. Among non-toxic thyroid nodules, a careful application of US risk stratification systems is pivotal to exclude inappropriate FNAC and guide the procedure on suspicious ones. However, almost one-third of cytology examinations are rendered as indeterminate, requiring “diagnostic surgery” to provide a definitive diagnosis. 99mTc-methoxy-isobutyl-isonitrile ([99mTc]Tc-MIBI) and [18F]fluoro-deoxy-glucose ([18F]FDG) molecular imaging can spare those patients from unnecessary surgeries. The clinical value of AI in the evaluation of thyroid nodules needs to be determined.

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“…If the TSH test indicates disease or the clinician suspects dysregulation of TH production, follow‐up tests involve measurement of free THs. Serum‐free T4 concentration is among the most commonly performed clinical diagnostic test and is essential whenever clinicians suspect that the thyroid gland produces too little or too much THs (for in‐depth reviews of clinical measurement of free TH 7 , 8 ). Thyroid diseases are prevalent in the global population: Hypothyroidism, a disease caused by insufficient concentrations of circulating THs, is by far the most common thyroid disease and affects up to 10% of the middle‐aged female population in developed countries.…”

Section: Introductionmentioning

confidence: 99%

Analysis of free, unbound thyroid hormones by liquid chromatography‐tandem mass spectrometry: A mini‐review of the medical rationale and analytical methods

Westbye,

Aas,

Kelp

et al. 2023

Analytical Science Advances

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Measurement of hormones is important for the diagnosis and management of endocrine diseases. The thyroid hormones thyroxine (T4) and triiodothyronine (T3) are among the most commonly measured hormones in clinical laboratories, and it is the concentration of free (not bound to proteins) thyroid hormones that is clinically most relevant. Free thyroid hormones are commonly measured using automated immunoassays, however, these are known to produce erroneous results due to interferences for some patients. Measurement of free thyroid hormones using equilibrium dialysis or ultrafiltration combined with liquid chromatography coupled to tandem mass spectrometry (LC‐MS/MS) is considered a more accurate and robust method for free thyroid hormone analysis and overcomes many of the limitations of immunoassays. However, LC‐MS/MS‐based methods are often considered too technically difficult and not amendable to high throughput by clinical chemists and are not offered by many clinical laboratories. This mini‐review aims to make it easier for clinical laboratories to implement LC‐MS/MS‐based measurement of free thyroid hormones. It describes the medical rationale for measuring free thyroid hormones, the benefits of LC‐MS/MS‐based methods with respect to interferences affecting immunoassay‐based methods and physical separation methods. This mini‐review highlights important parameters for ultrafiltration and equilibrium dialysis to obtain physiologically relevant free thyroid hormone concentrations and focuses on methods and devices used in clinical chemistry.

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Free thyroxine measurement in clinical practice: how to optimize indications, analytical procedures, and interpretation criteria while waiting for global standardization

Cited by 10 publications

References 256 publications

Specific effects on the thyroid relevant for performing a dietary cumulative risk assessment of pesticide residues: 2024 update

Specific effects on the thyroid relevant for performing a dietary cumulative risk assessment of pesticide residues: 2024 update

Integrated Diagnostics of Thyroid Nodules

Analysis of free, unbound thyroid hormones by liquid chromatography‐tandem mass spectrometry: A mini‐review of the medical rationale and analytical methods

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