Analytical and Clinical Evaluation of Three Sensitive Thyrotropin Assays

Three sensitive assays (Behring, Organon and LKB-Pharmacia) for measurement of serum thyrotropin (TSH) were evaluated. All three assays showed good precision, sensitivity, linearity and for practical purposes negligible high dose hook effects. The correlations between the assays were excellent, but due to standardisation and/or matrix effects there were incomplete recoveries in two kits and the kits showed systematic differences of up to 20% in the TSH values obtained. The clinical utility of the three assays was investigated in patients with thyroidal and non-thyroidal illnesses and in healthy subjects with thyroxine binding abnormalities. According to the results of the analytical and clinical evaluation, all three kits are acceptable and reliable as first-line thyroid function tests.

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THERAPY OF ENDOCRINE DISEASE: T4 + T3 combination therapy: is there a true effect?

Acta Endocrinologica ◽

10.1530/eje-17-0645 ◽

2017 ◽

Vol 177 (6) ◽

pp. R287-R296 ◽

Cited By ~ 21

Author(s):

Wilmar M Wiersinga

Keyword(s):

Combination Therapy ◽

Thyroid Function ◽

Healthy Subjects ◽

Randomized Clinical Trials ◽

Peripheral Tissue ◽

Thyroid Function Tests ◽

Peripheral Tissues ◽

Persistent Symptoms ◽

Function Tests ◽

Number Of Patients

About 5%–10% of hypothyroid patients on T4 replacement therapy have persistent symptoms, despite normal TSH levels. It was hoped that T4 + T3 combination therapy might provide better outcomes, but that was not observed according to a meta-analysis of 11 randomized clinical trials comparing T4 monotherapy with T4 + T3 combination therapy. However, the issue is still subject of much research because normal thyroid function tests in serum may not necessarily indicate an euthyroid state in all peripheral tissues. This review evaluates recent developments in the field of T4 + T3 combination therapy. T4 monotherapy is associated with higher serum FT4 levels than in healthy subjects, and subnormal serum FT3 and FT3/FT4 ratios are observed in about 15% and 30% respectively. T4 + T3 combination therapy may mimic more closely thyroid function tests of healthy subjects, but it has not been demonstrated that relatively low serum FT3 or FT3/FT4 ratios are linked to persistent symptoms. One study reports polymorphism Thr92Ala in DIO2 is related to lower serum FT3 levels after thyroidectomy, and that the D2-Ala mutant reduces T4 to T3 conversion in cell cultures. Peripheral tissue function tests such as serum cholesterol reflect thyroid hormone action in target tissues. Using such biochemical markers, patients who had a normal serum TSH during postoperative T4 monotherapy, were mildly hypothyroid, whereas those with a TSH 0.03–≤0.3 mU/L were closest to euthyroidism. Peripheral tissue function tests suggest euthyroidism more often in patients randomized to T4 + T3 rather than that to T4. Preference for T4 + T3 combination over T4 monotherapy was dose-dependently related to the presence of two polymorphisms in MCT10 and DIO2 in one small study. It is not known if persistent symptoms during T4 monotherapy disappear by switching to T4 + T3 combination therapy. The number of patients on T4 + T3 therapy has multiplied in the last decade, likely induced by indiscriminate statements on the internet. Patients are sometimes not just asking but rather demanding this treatment modality. It creates tensions between patients and physicians. Only continued research will answer the question whether or not T4 + T3 combination therapy has true benefits in some patients.

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First-line thyroid function tests − TSH alone is not enough

Clinical Endocrinology ◽

10.1046/j.1365-2265.2003.01690.x ◽

2003 ◽

Vol 58 (1) ◽

pp. 20-21 ◽

Cited By ~ 22

Author(s):

G. J. Beckett ◽

A. D. Toft

Keyword(s):

Thyroid Function ◽

Thyroid Function Tests ◽

First Line ◽

Function Tests

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Effect of High-dose Biotin on Thyroid Function Tests: Case Report and Literature Review

Cureus ◽

10.7759/cureus.2845 ◽

2018 ◽

Author(s):

Arash Ardabilygazir ◽

Sonia Afshariyamchlou ◽

Danial Mir ◽

Issac Sachmechi

Keyword(s):

Case Report ◽

Literature Review ◽

Thyroid Function ◽

High Dose ◽

Thyroid Function Tests ◽

Function Tests

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The method comparison and the verification of precision of Mindray CL-6000i thyroid function tests (TFTs)

Turkish Journal of Biochemistry ◽

10.1515/tjb-2019-0506 ◽

2020 ◽

Vol 0 (0) ◽

Author(s):

Giray Bozkaya ◽

Ali Rıza Şişman

Keyword(s):

Thyroid Function ◽

Method Comparison ◽

Endocrine Disorders ◽

Thyroid Function Tests ◽

Good Precision ◽

Serum Samples ◽

Function Tests ◽

The Mean ◽

The Difference ◽

Mean Differences

AbstractObjectivesThyroid diseases are the most frequent endocrine disorders and thyroid function tests (TFTs) are the most commonly requested endocrine tests. The reliable measurements of these tests are quite important. The aim of our study was to determine the bias and to verify the precision of the newly introduced Mindray CL-6000i immunoassay system in the guidance of CLSI guidelines.MethodsA precision and bias study was performed in Mindray CL-6000i analyzer for FT3, FT4, TSH, Anti-TG, and Anti-TPO tests by using BioRad quality control (QC) materials and serum samples, respectively. Bland–Altman difference plot and Passing-Bablok regression analysis was made for method comparison with Beckman Coulter DXI 800 analyzer.ResultsThe repeatability coefficient of variations (CVs) of FT3, FT4, TSH, Anti-TG, and Anti-TPO tests were ≤2.36, ≤1.66, ≤2.38, ≤3.48, and ≤3.31% while within laboratory CVs were ≤2.85, ≤4.61, ≤2.59, ≤3.78, and ≤3.60%, respectively. The mean differences between the two methods obtained from Bland–Altman analysis for FT3, FT4, TSH, Anti-TG, and Anti-TPO were defined to be −19%, 1.95%, −5.9%, −3.5%, and 7.3%, respectively.ConclusionsMindray CL-6000i had good precision in all tests, but the difference between the two methods in some tests shows that the harmonization and standardization of TFTs initiated globally is required.

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CLINICAL EVALUATION OF FREE T4 TESTS AS A SCREENING TEST AND CORRELATION TO OTHER THYROID FUNCTION TESTS

Clinical Nuclear Medicine ◽

10.1097/00003072-198210001-00016 ◽

1982 ◽

Vol 7 (supplement) ◽

pp. P66

Author(s):

A. V. Heal ◽

F. S. Ashkar ◽

C. W. Butler ◽

A. Caffarena

Keyword(s):

Thyroid Function ◽

Clinical Evaluation ◽

Screening Test ◽

Thyroid Function Tests ◽

Free T4 ◽

Function Tests

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Clinicopathological study of asymptomatic thyroid swelling and its correlation with thyroid function tests

International Journal of Otorhinolaryngology and Head and Neck Surgery ◽

10.18203/issn.2454-5929.ijohns20191739 ◽

2019 ◽

Vol 5 (3) ◽

pp. 727

Author(s):

Anuja Bhargava ◽

Syed M. Faiz ◽

M. Shakeel ◽

Nafas J. Singh ◽

Saloni Singh

Keyword(s):

Thyroid Function ◽

Follicular Adenoma ◽

Clinical Findings ◽

Thyroid Function Tests ◽

First Line ◽

Function Tests ◽

Cystic Changes ◽

Thyroid Swelling ◽

Thyroid Profile ◽

Underlying Pathology

Background: Thyroid swelling without symptomatic manifestation is common occurrence and could affect 5 to 20% patients in endemic areas. Majority of them are non neoplastic and may not require surgery. Less than 5% of thyroid nodules are malignant.Methods: Present study was conducted to correlate clinical findings, HRUSG findings, thyroid profile and FNAC findings in patients of asymptomatic thyroid swelling. Results: Proportion of euthyroid patients was higher compared to hyperthyroid and hypothyroid diagnosed as colloid goiter on FNAC findings (82.4% vs. 0.0% and 12.9%). Proportion of hypothyroid was higher compared to euthyroid and hyperthyroid diagnosed as Follicular adenoma (3.2% vs. 0.0% and 1.2%) and colloid goiter with cystic changes (48.4% vs. 0.0% and 10.6%). Proportion of hyperthyroid compared to hypothyroid and euthyroid patients were higher diagnosed as thyroiditis (75.0% vs. 32.3% and 5.9%) and papillary/medullary CA (25.0% vs. 3.2 and 0.0%). A statistically significant association of FNAC diagnosis and thyroid profile of patients with asymptomatic thyroid swelling was found.Conclusions: The present study showed that thyroid dysfunction could play a significant role in determining the underlying pathology behind thyroid swelling and must be evaluated at the earliest using thyroid function tests as the first line of diagnostic tool. In case of suspected thyroid profile; USG neck and FNAC should be done. In view of lack of studies correlating thyroid and clinicopathological profiles of thyroid swellings, further studies to potentiate the present study findings are recommended.

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