scholarly journals Misleading results from immunoassays of serum free thyroxine in the presence of rheumatoid factor

1997 ◽  
Vol 43 (6) ◽  
pp. 957-962 ◽  
Author(s):  
Anthony G W Norden ◽  
Rodwin A Jackson ◽  
Lorraine E Norden ◽  
A Jane Griffin ◽  
Margaret A Barnes ◽  
...  
Keyword(s):  
Thyroid Hormone ◽  
Rheumatoid Factor ◽  
Equilibrium Dialysis ◽  
Thyroid Stimulating Hormone ◽  
Normal Serum ◽  
Free Thyroxine ◽  
Free Triiodothyronine ◽  
Serum Free ◽  
Serum Free Thyroxine ◽  
Stimulating Hormone

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.

A Case Series of Patients With Central Hypothyroidism From Oxcarbazepine Therapy

2020 ◽  
pp. 088307382096292 ◽  
Author(s):  
Bahareh Michelle Schweiger ◽  
Aaron-James Lao ◽  
Jane Tavyev
Keyword(s):  
Thyroid Function ◽  
Pediatric Population ◽  
Case Series ◽  
Metabolic Enzymes ◽  
Thyroid Stimulating Hormone ◽  
Free Thyroxine ◽  
Central Hypothyroidism ◽  
Serum Free ◽  
Serum Free Thyroxine ◽  
Stimulating Hormone

Many medications can impact thyroid function. Antiseizure medications have been shown to disrupt thyroid function in adults, but information is limited about how antiseizure medications may affect thyroid function in children. Oxcarbazepine is an analog of carbamazepine designed to minimize effects from the hepatic P450 metabolic enzymes. We have found that in the pediatric population, serum free thyroxine is reduced and thyroid-stimulating hormone concentrations are unchanged in patients taking oxcarbazepine with the mechanism thus being central hypothyroidism.

Serum free thyroxine in patients with T3-toxicosis

1985 ◽  
Vol 110 (3) ◽  
pp. 354-359 ◽  
Author(s):  
Enio Martino ◽  
Alessandro Pacchiarotti ◽  
Fabrizio Aghini-Lombardi ◽  
Lucia Grasso ◽  
Giovanni Bambini ◽  
...  
Keyword(s):  
Clinical Evidence ◽  
Elevated Serum ◽  
Normal Serum ◽  
Free Thyroxine ◽  
Total Serum ◽  
Free Triiodothyronine ◽  
Serum Free ◽  
Serum Thyroxine ◽  
Free Thyroxine Index ◽  
Serum Free Thyroxine

Abstract. The serum free thyroxine concentration was measured by direct radioimmunoassay in 38 untreated T3-thyrotoxic patients with elevated serum total and free triiodothyronine, normal serum thyroxine and free thyroxine index, no TSH response to TRH, and with clinical evidence of hyperthyroidism. An elevation of circulating free thyroxine values was observed in 58% of the patients, whereas total serum thyroxine concentration was within the normal range. It is suggested, therefore, that T3-thyrotoxicosis should be reserved for patients with elevated serum total T3 and free T3 concentrations and normal serum total T4 and free T4 concentrations. Serum thyroxine-binding globulin concentrations were significantly lower (P < 0.025) in patients with an elevated serum free thyroxine (18.7 ± 3.6 μg/ml: mean ± sd) as compared with those in patients with a normal free thyroxine concentration (23.4 ± 2.6 μg/ml). In addition, no daily fluctuations in total and free thyroxine concentration were observed in 6 patients over a 4–8 day period.

scholarly journals Thyroid Hormone levels in Highlanders- A Comparison Between Residents of Two Altitudes in Nepal

2014 ◽  
Vol 11 (1) ◽  
pp. 18-21 ◽  
Author(s):  
O Nepal ◽  
BR Pokharel ◽  
K Khanal ◽  
P Gyawali ◽  
SL Malik ◽  
...  
Keyword(s):  
Thyroid Hormone ◽  
Thyroid Hormones ◽  
High Altitude ◽  
Thyroid Stimulating Hormone ◽  
Free Thyroxine ◽  
High Altitudes ◽  
Free Triiodothyronine ◽  
Sea Bed ◽  
High Altitude Natives ◽  
Stimulating Hormone

Background The endocrine changes related to altitude adaptation in human have attracted physiologists around the globe for long. A number of high altitude studies to detect the physiological changes have been performed now and then. But, the study to see the hormonal changes to compare populations residing at different high altitudes is a scarce. Hence, we have performed a study in native populations of different high altitude comparing changes in thyroid hormones in western Nepal. The Jharkot population included in this study is at altitude of 3760m and Jomsom population at 2800m height from sea bed. Objective The study is to compare changes in thyroid hormones at two different high altitude natives. Methods To compare thyroid status between high altitude natives at two different altitudes a cross sectional study is performed by random sampling method. The blood sample was collected in a vacutainer from fifty eight individuals after obtaining the informed consent of participants. The blood collected from antecubital vein was centrifuged in an hour and the serum obtained was used for biochemical analysis of free triiodothyronine, free thyroxine and thyroid stimulating hormone. Results Mean free thyroxine (fT4) of Jharkot population is significantly larger (p = 0.001) than Jomsom population. Mean thyroid stimulating hormone (TSH) with p = 0.597, does not indicate the difference between this two population. There is no significant difference between mean free triiodothyronine (fT3) of Jharkot and Jomsom population (p = 0.345). Conclusion The rise in free thyroid hormone at high altitude is not dependent on the thyroid stimulating hormone released from anterior pituitary. The rise in free thyroxine is found at higher altitude and no difference in fT3 level is detected in population studied at high altitudes. DOI: http://dx.doi.org/10.3126/kumj.v11i1.11017 Kathmandu University Medical Journal Vol.11(1) 2013: 18-21

Establishment of Early Pregnancy Related Thyroid Hormone Models and Reference Intervals for Pregnant Women in China Based on Real World Data

2021 ◽  
Vol 53 (04) ◽  
pp. 272-279
Author(s):  
Chaochao Ma ◽  
Xiaoqi Li ◽  
Lixin Liu ◽  
Xinqi Cheng ◽  
Fang Xue ◽  
...  
Keyword(s):  
Thyroid Hormone ◽  
Thyroid Hormones ◽  
Pregnant Women ◽  
Early Pregnancy ◽  
Gestational Age ◽  
Dynamic Change ◽  
Reference Intervals ◽  
Thyroid Stimulating Hormone ◽  
Free Thyroxine ◽  
Stimulating Hormone

AbstractThyroid hormone reference intervals are crucial for diagnosing and monitoring thyroid dysfunction during early pregnancy, and the dynamic change trend of thyroid hormones during pregnancy can assist clinicians to assess the thyroid function of pregnant women. This study aims to establish early pregnancy related thyroid hormones models and reference intervals for pregnant women. We established two derived databases: derived database* and derived database#. Reference individuals in database* were used to establish gestational age-specific reference intervals for thyroid hormones and early pregnancy related thyroid hormones models for pregnant women. Individuals in database# were apparently healthy non-pregnant women. The thyroid hormones levels of individuals in database# were compared with that of individuals in database* using nonparametric methods and the comparative confidence interval method. The differences in thyroid stimulating hormone and free thyroxine between early pregnant and non-pregnant women were statistically significant (p<0.0001). The reference intervals of thyroid stimulating hormone, free thyroxine and free triiodothyronine for early pregnant women were 0.052–3.393 μIU/ml, 1.01–1.54 ng/dl, and 2.51–3.66 pg/ml, respectively. Results concerning thyroid stimulating hormone and free thyroxine reference intervals of early pregnancy are comparable with those from other studies using the same detection platform. Early pregnancy related thyroid hormones models showed various change patterns with gestational age for thyroid hormones. Early pregnancy related thyroid hormones models and reference intervals for pregnant women were established, so as to provide accurate and reliable reference basis for the diagnosing and monitoring of maternal thyroid disfunction in early pregnancy.

Subclinical Hyperthyroidism: Diagnostic Criteria and Principles of Treatment

2016 ◽  
pp. 75-79
Author(s):  
Vita Galitskaya
Keyword(s):  
Hormone Receptors ◽  
Color Doppler ◽  
Specific Treatment ◽  
Nodular Goiter ◽  
Thyroid Stimulating Hormone ◽  
Free Thyroxine ◽  
Subclinical Hyperthyroidism ◽  
Mineral Density ◽  
Free Triiodothyronine ◽  
Stimulating Hormone

This article presents the European Thyroid Association guidelines for diagnosis and treatment of subclinical hyperthyroidism, 2015. Determination of thyroid1stimulating hormone levels can help to diagnose a variety of pathological conditions: hypertension, cardiac fibrillation, atrial fibrillation, mineral density reduction in bones, menstrual irregularities, infertility, which require specific treatment after detection of hormonal status disorders (subclinical, overt), taking into account the patient’s age. Diagnosis of endogenous subclinical hyperthyroidism is based solely on the results of laboratory tests, not clinical criteria. Endogenous subclinical hyperthyroidism is defined by the presence of sub-normal levels of thyroid-stimulating hormone with normal levels of free thyroxine, total triiodothyronine, and/or free triiodothyronine. There are two categories of endogenous subclinical hyperthyroidism: stage 1 – the level of thyroid-stimulating hormone is 0,1–0,39 mIU/l; stage 2 – the level of thyroid-stimulating hormone is <0.1 mIU/l. The levels of free thyroxine and free triiodothyronine, as a rule, are medium-high value at a subclinical level of thyroid hormone and can help differentiate between endogenous subclinical hyperthyroidism from overt hyperthyroidism. It is recommended to study the thyroid-stimulating hormone level as the first test for the diagnosis of subclinical hyperthyroidism. In identifying low levels of thyroid-stimulating hormone it is necessary to investigate the level of free thyroxine, free or bound triiodothyronine. Patients with primary sub-normal levels of thyroid-stimulating hormone with concentration of thyroid hormones in the upper limit or in normal range should be evaluated within 2-3 months. It is recommended to perform scintigraphy and possible 24-hour test the absorption of radioactive iodine if in patient with 2nd degree endogenous subclinical hyperthyroidism there is nodular goiter to determine treatment strategy. Ultrasonography with color Doppler can be informative for patients with endogenous subclinical hyperthyroidism and nodular goiter. Determining the level of antibodies to thyroid-stimulating hormone receptors can confirm the etiology of autoimmune-induced hyperthyroidism.

Circadian thyrotropin variations are preserved in normal pregnant women

1995 ◽  
Vol 133 (1) ◽  
pp. 71-74 ◽  
Author(s):  
Elio Roti ◽  
Luigi Bartalena ◽  
Roberta Minelli ◽  
Mario Salvi ◽  
Eliana Gardini ◽  
...  
Keyword(s):  
Circadian Rhythm ◽  
Pregnant Women ◽  
Free Thyroxine ◽  
Third Trimester ◽  
Circadian Variations ◽  
Free Triiodothyronine ◽  
Serum Free ◽  
Trimester Pregnancy ◽  
Serum Tsh ◽  
Serum Free Thyroxine

Roti E, Bartalena L, Minelli R, Salvi M, Gardini E, Pistolesi A, Martino E, Braverman LE. Circadian thyrotropin variations are preserved in normal pregnant women. Eur J Endocrinol 1995;133:71–4. ISSN 0804–4643 Serum thyrotropin (TSH) concentration circadian rhythm is abolished in many endocrine and nonendocrine diseases. In the present study we have measured serum TSH concentration over 24 h every 2 h in second and third trimester pregnant women. During the 24-h period, serum free thyroxine and free triiodothyronine concentrations did not change significantly. In contrast, serum TSH concentrations demonstrated significant circadian variations both in the second and third trimester pregnant women (p<0.02 and p <0.005, respectively). In summary, second and third trimester pregnancy is associated with a normal circadian TSH rhythm. Elio Roti, Centro per lo Studio, Prevenzione, Diagnosi e Cura delle Tireopatie, University of Parma, via Gramsci 14, 1-43100 Parma, Italy

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