Studies on Thyroid Hormone Autoantibody in Two Euthyroid Cases with Spuriously High Value of Serum Free Triiodothyronine

Abstract A novel interference with measurements of serum free thyroxine (FT4) caused by rheumatoid factor (RhF) is described. We found misleading, sometimes gross, increases of FT4 results in 5 clinically euthyroid elderly female patients with high RhF concentrations. All 5 patients had high FT4 on Abbott AxSYM® or IMx® analyzers. “NETRIA” immunoassays gave misleading results in 4 of the 5 patients; Amerlex-MAB® in 2 of 4 patients; AutoDELFIA®in 2 of the 5; and Corning ACS-180® and Bayer Diagnostics Immuno 1® in 1 of the 5. BM-ES700® system results for FT4 in these women remained within the reference range. Results for serum T4, thyroid-stimulating hormone, free triiodothyronine, thyroid-hormone-binding globulin, and FT4 measured by equilibrium dialysis were normal in all 5 patients. Drugs, albumin-binding variants, and anti-thyroid-hormone antibodies were excluded as interferences. Addition to normal serum of the RhF isolated from each of the 5 patients increased the apparent FT4 (Abbott AxSYM). Screening of 83 unselected patients demonstrated a highly significant positive correlation between FT4 (Abbott AxSYM) and RhF concentrations. Discrepant, apparently increased FT4 with a normal result for thyroid-stimulating hormone should lead to measurement of the patient’s RhF concentration.

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Familial Dysalbuminemic Hyperthyroxinemia in a Japanese Man Caused by a Point Albumin Gene Mutation (R218P)

Japanese Clinical Medicine ◽

10.4137/jcm.s38990 ◽

2016 ◽

Vol 7 ◽

pp. JCM.S38990 ◽

Cited By ~ 6

Author(s):

Yoshinori Osaki ◽

Yoshitaka Hayashi ◽

Yoshinori Nakagawa ◽

Katsumi Yoshida ◽

Hiroshi Ozaki ◽

...

Keyword(s):

Thyroid Hormone ◽

Autosomal Dominant ◽

Japanese Patients ◽

Free Triiodothyronine ◽

Serum Free ◽

Albumin Gene ◽

Dominant Disease ◽

Euthyroid Hyperthyroxinemia ◽

Aomori Prefecture ◽

Tsh Levels

Familial dysalbuminemic hyperthyroxinemia (FDH) is a familial autosomal dominant disease caused by mutation in the albumin gene that produces a condition of euthyroid hyperthyroxinemia. In patients with FDH, serum-free thyroxine (FT4) and free triiodothyronine (FT3) concentrations as measured by several commercial methods are often falsely increased with normal thyrotropin (TSH). Therefore, several diagnostic steps are needed to differentiate TSH-secreting tumor or generalized resistance to thyroid hormone from FDH. We herein report a case of a Japanese man born in Aomori prefecture, with FDH caused by a mutant albumin gene (R218P). We found that a large number of FDH patients reported in Japan to date might have been born in Aomori prefecture and have shown the R218P mutation. In conclusion, FDH needs to be considered among the differential diagnoses in Japanese patients born in Aomori prefecture and showing normal TSH levels and elevated FT4 levels.

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Elevated serum levels of free triiodothyronine in adolescent boys with gynaecomastia compared with controls

Acta Endocrinologica ◽

10.1530/eje-13-0847 ◽

2014 ◽

Vol 171 (2) ◽

pp. 193-198 ◽

Cited By ~ 2

Author(s):

Mikkel G Mieritz ◽

Kaspar Sorensen ◽

Lise Aksglaede ◽

Annette Mouritsen ◽

Casper P Hagen ◽

...

Keyword(s):

Thyroid Hormone ◽

Elevated Serum ◽

Serum Levels ◽

Adolescent Boys ◽

Free Triiodothyronine ◽

Pubertal Stage ◽

Cross Sectional ◽

Healthy Adolescent ◽

Serum Free ◽

Thyroid Hormone Levels

ObjectivePubertal gynaecomastia is a frequent phenomenon occurring in 20–40% of otherwise healthy adolescent boys. Little is known about the aetiology of pubertal gynaecomastia. Markedly elevated thyroid hormone levels in adults with hyperthyroidism are associated with gynaecomastia.DesignA cross-sectional examination of 444 healthy boys with and without pubertal gynaecomastia.MethodsWe evaluated TSH, triiodothyronine (T3), thyroxine (T4), free T4 and free T3 in a cohort of healthy boys with and without pubertal gynaecomastia.ResultsBoys with gynaecomastia had significantly higher serum free T3, even after correction for age, BMI and pubertal stage. After inclusion of IGF1 in the model the differences disappeared. TSH, T4, free T4 and T3 did not differ between the groups.ConclusionsWe speculate that the GH/IGF1 axis and thyroid hormones interact and influence the development of pubertal gynaecomastia.

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Genetic and environmental interrelations between measurements of thyroid function in a healthy Danish twin population

AJP Endocrinology and Metabolism ◽

10.1152/ajpendo.00321.2006 ◽

2007 ◽

Vol 292 (3) ◽

pp. E765-E770 ◽

Cited By ~ 25

Author(s):

Pia Skov Hansen ◽

Thomas Heiberg Brix ◽

Ivan Iachine ◽

Thorkild I. A. Sørensen ◽

Kirsten Ohm Kyvik ◽

...

Keyword(s):

Thyroid Hormone ◽

Thyroid Function ◽

Free Triiodothyronine ◽

Environmental Correlations ◽

Serum Free ◽

Hormone Levels ◽

Opposite Sex ◽

Thyroid Hormone Levels ◽

Serum Tsh ◽

Danish Twin

Serum thyrotropin (TSH), free thyroxine (T4), and free triiodothyronine (T3) levels illustrate the thyroid function set point, but the interrelations between these have never been characterized in detail. The aim of this study was to examine the associations between TSH and thyroid hormone levels in healthy euthyroid twins and to determine the extent to which the same genes influence more than one of these biochemical traits; 1,380 healthy euthyroid Danish twins (284 monozygotic, 286 dizygotic, 120 opposite-sex twin pairs) were recruited. Genetic and environmental associations between thyroid function measurements were examined using quantitative genetic modeling. In bivariate genetic models, the phenotypic relation between two measurements was divided into genetic and environmental correlations. Free T4 and free T3 levels were positively correlated ( r = 0.32, P < 0.0001). The genetic correlation between serum free T4 and free T3 levels was rg = 0.25 (95% CI 0.14–0.35), suggesting that a set of common genes affect both phenotypes (pleiotropy). The correlation between the environmental effects was re = 0.41 (0.32–0.50). From this we calculated that the proportion of the correlation between free T4 and free T3 levels mediated by common genetic factors was 48%. Only 7% of the genetic component of serum free T3 levels is shared with serum free T4. Serum TSH and thyroid hormone levels did not share any genetic influences. In conclusion, thyroid hormone levels are partly genetically correlated genes that affect free T4 levels and exert pleiotropic effects on free T3 levels, although most of the genetic variance for these measurements is trait specific.

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Effects of Age and Health on the Euthyroid Reference Ranges for Serum Free Thyroxine and Free Triiodothyronine

Nuklearmedizin ◽

10.1055/s-0038-1624280 ◽

1985 ◽

Vol 24 (02) ◽

pp. 57-65 ◽

Cited By ~ 6

Author(s):

J. E. M. Midgley ◽

K. R. Gruner

Keyword(s):

Lower Limit ◽

Healthy Subjects ◽

Thyroid Dysfunction ◽

Reference Range ◽

Free Thyroxine ◽

Reference Ranges ◽

Free Triiodothyronine ◽

Serum Free ◽

Young Subjects ◽

Age Range

SummaryAge-related trends in serum free thyroxine (FT4) and free triiodothyronine (FT3) concentrations were measured in 7248 euthyroid subjects (age-range 3 months to 106 years). 5700 were patients referred to hospitals for investigation of suspected thyroid dysfunction, but who were diagnosed euthyroid. 1548 were healthy blood donors (age-range 18-63 years) with no indication of thyroid dysfunction. FT4 concentrations were little affected by the age, the sex or the state of health of the subjects in either group. Serum FT3 concentrations were significantly affected by both age and health factors. The upper limit of the euthyroid reference range for young subjects up to 15 years was about 20% higher (10.4 pmol/1) than for adult subjects older than 25 years (8.8 pmol/1). The change in the upper limits typical of young subjects to that typical of adults occurred steadily over the decade 15–25 years. After this age, little further change occurred, especially in healthy subjects. Additionally, the lower limit of the euthyroid range for FT3 was extended by the inclusion in the reference group of patients referred to hospitals. Compared with the lower limit of the FT3 range for healthy subjects (5 pmol/1), the corresponding limit for referred subjects (young or adult) was 3.5–3.8 pmol/1. Broadening of the FT3 reference range was probably brought about by a significant number of patients in the hospital-referred group with the “1OW-T3 syndrome” of mild non-thyroidal illness. Accordingly, FT3 was inferior to FT4 in the discrimination of hypothyroidism, as FT4 was unaffected by this phenomenon. Effects of age and non-thyroidal illness on serum FT3 concentrations require great care when selecting subjects for a laboratory euthyroid reference range typical of the routine workload. Constraints on the choice of subjects for FT4 reference ranges are less stringent.

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Early change of thyroid hormone concentration after 131I treatment in patients with solitary toxic adenoma

Nuklearmedizin ◽

10.1055/s-0038-1623893 ◽

2002 ◽

Vol 41 (04) ◽

pp. 178-183 ◽

Cited By ~ 1

Author(s):

V. Fidler ◽

K. Zaletel ◽

S. Gaberšček ◽

S. Hojker ◽

E. Pirnat

Keyword(s):

Thyroid Hormone ◽

Antithyroid Drugs ◽

Prospective Clinical Study ◽

Hormone Concentration ◽

Toxic Adenoma ◽

Free Triiodothyronine ◽

Thyroid Cells ◽

131I Treatment ◽

Before And After ◽

Thyroid Hormone Concentration

Summary Aim: In spite of extensive use of 131I for treatment of hyperthyroidism, the results of early outcome are variable. In our prospective clinical study we tested whether 131I induced necrosis causing clinical aggravation of hyperthyroidism and increasing the free thyroid hormone concentration in the serum of patients with solitary toxic adenoma not pretreated with antithyroid drugs. Patients and methods: 30 consecutive patients were treated with 925 MBq 131I. Serum concentration of thyrotropin (TSH), free thyroxine (fT4), free triiodothyronine (fT3), thyroglobulin (Tg), and interleukin-6 (IL-6) were measured before and after application of 131I. Results: After application of 131I no clinical worsening was observed. FT4 and fT3 concentration did not change significantly within the first five days, whereas both of them significantly decreased after 12 days (p <0.0001). Slight and clinically irrelevant increase in the level of the two thyroid hormones was observed in 9 patients. Furthermore, we observed a prolonged increase in Tg concentration and a transient increase in IL-6 concentration. Conclusion: Neither evidence of any clinical aggravation of hyperthyroidism nor any significant increase in thyroid hormone concentration by 131I induced necrosis of thyroid cells was found. Therefore, the application of 131I may be considered as a safe and effective treatment for patients with hyperthyroidism due to toxic adenoma.

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