Preliminary Evaluation of a Fluorescence Polarization Immunoassay (Abbott TDx) for Estimating Serum Free Thyroxine Concentrations in Patients with Critical Nonthyroid Illness and Low Total Thyroxine Concentrations in Serum

1992 ◽  
Vol 38 (9) ◽  
pp. 1916-1917 ◽  
Author(s):  
C M Mendel
Keyword(s):  
Fluorescence Polarization ◽  
Free Thyroxine ◽  
Preliminary Evaluation ◽  
Fluorescence Polarization Immunoassay ◽  
Serum Free ◽  
Total Thyroxine ◽  
Serum Free Thyroxine

scholarly journals Serum Free Thyroxine Concentrations in Subjects with High Circulating Levels of Thyroxine-Binding Globulin

1983 ◽  
Vol 20 (5) ◽  
pp. 285-288 ◽  
Author(s):  
K Ashwell ◽  
M R Hopton ◽  
J S Harrop
Keyword(s):  
Free Thyroxine ◽  
Control Group ◽  
Serum Free ◽  
Thyroxine Binding Globulin ◽  
Respective Control Group ◽  
Factor Ii ◽  
Total Thyroxine ◽  
Hormone Binding Protein ◽  
Circulating Levels ◽  
Serum Free Thyroxine

Serum free thyroxine (FT4) and thyroid hormone-binding protein concentrations were measured in pregnant women, stilboestrol-treated patients, and subjects with congenital thyroxine-binding-globulin (TBG) excess. In pregnant and stilboestrol-treated patients matched for TBG concentrations, serum FT4 concentrations measured by the Amerlex technique and by calculation, were reduced, as also was the total thyroxine (TT4)/TBG ratio. In congenital TBG excess Amerlex and calculated FT4 concentrations were normal whereas the TT4/TBG ratio was low. In contrast to the Amerlex method, FT4 concentrations by the Immophase procedure were normal in pregnant and stilboestrol-treated individuals and high in congenital TBG excess. We conclude that (i) reduced FT4 concentrations in pregnancy are related to an oestrogen effect rather than to some other pregnancy-associated factor, (ii) the TT4/TBG ratio gives a misleading indication of FT4 concentration in congenital TBG excess, and (iii) that when TBG concentrations are raised Immophase gives higher FT4 values than Amerlex or calculation when each is compared to FT4 values in their normal respective control group.

Factors Affecting the Serum Free Thyroxine Levels in Hospitalized Chronic Geriatric Patients

1993 ◽  
Vol 41 (7) ◽  
pp. 742-746 ◽  
Author(s):  
Istvan Szabolcs ◽  
Christoph Ploenes ◽  
Mathias Beyer ◽  
Wolfdieter Bernard ◽  
Jorg Herrmann
Keyword(s):  
Geriatric Patients ◽  
Free Thyroxine ◽  
Factors Affecting ◽  
Serum Free ◽  
Serum Free Thyroxine

scholarly journals Serum Free Thyroxine and Triiodothyronine Concentrations in Subacute Thyroiditis

1980 ◽  
Vol 56 (11) ◽  
pp. 1527-1534
Author(s):  
Katsumi YOSHIDA ◽  
Toshiro SAKURADA ◽  
Nobuko KAISE ◽  
Kazuo KAISE ◽  
Hirofumi KITAOKA ◽  
...  
Keyword(s):  
Free Thyroxine ◽  
Subacute Thyroiditis ◽  
Serum Free ◽  
Serum Free Thyroxine

scholarly journals Serum free thyroxine levels are associated with the efficacy of weight reduction therapy in obese female patients

2016 ◽  
Vol 63 (3) ◽  
pp. 221-229 ◽  
Author(s):  
Koshi Hashimoto ◽  
Tetsuya Tagami ◽  
Hajime Yamakage ◽  
Kazuya Muranaka ◽  
Masashi Tanaka ◽  
...  
Keyword(s):  
Weight Reduction ◽  
Free Thyroxine ◽  
Serum Free ◽  
Female Patients ◽  
Obese Female ◽  
Serum Free Thyroxine

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.

Variations in Serum Free Thyroxine Concentration Within the Reference Range Predicts the Incidence of Metabolic Syndrome in Non-Obese Adults: A Cohort Study

Thyroid ◽  
2017 ◽  
Vol 27 (7) ◽  
pp. 886-893 ◽  
Author(s):  
Ladan Mehran ◽  
Atieh Amouzegar ◽  
Mahmood Bakhtiyari ◽  
Mohammad Ali Mansournia ◽  
Parnian Kheirkhah Rahimabad ◽  
...  
Keyword(s):  
Metabolic Syndrome ◽  
Cohort Study ◽  
Reference Range ◽  
Free Thyroxine ◽  
Obese Adults ◽  
Serum Free ◽  
Serum Free Thyroxine
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