fT3 & fT4Evidence & Dosage
Free thyroid hormones — peripheral conversion and activity.
Evidence at a glance
- Total studies
- 350
- With abstract
- 50
- Meta / Systematic / RCT
- 2
- Highly cited
- 50
- Publication years
- 1975–2026
fT3 & fT4 in the context of Hormones
This topic is part of our "Hormones" world. There you'll find methodology, evidence and the highest-impact levers — plus the order in which they sensibly build on each other.
Go to HormonesTop studies on fT3 & fT4
Ranked by influential-citation count and publication year.
TSH and FT4 Reference Interval Recommendations and Prevalence of Gestational Thyroid Dysfunction: Quantification of Current Diagnostic Approaches
The Journal of Clinical Endocrinology & Metabolism2023n=49638 influential citationsContext Guidelines recommend use of population- and trimester-specific thyroid-stimulating hormone (TSH) and free thyroxine (FT4) reference intervals (RIs) in pregnancy. Since these are often unavailable, clinicians frequently rely on…
Should we depend on reference intervals from manufacturer package inserts? Comparing TSH and FT4 reference intervals from four manufacturers with results from modern indirect methods and the direct method
Clinical Chemistry and Laboratory Medicine (CCLM)202433 influential citations<h4>Objectives</h4>Correct interpretation of thyroid function tests relies on correct reference intervals (RIs) for thyroid-stimulating hormone (TSH) and free thyroxine (FT4). ISO15189 mandates periodic verification of RIs, but…
A Longitudinal Study of Thyroid Markers Across Pregnancy and the Risk of Gestational Diabetes.
The Journal of clinical endocrinology and metabolism2018n=2,80232 influential citationsContext T3 is the biologically active thyroid hormone involved in glucose metabolism. The free T3 (fT3)/free T4 (fT4) ratio, a marker indicating conversion of fT4 to fT3, is also implicated in glucose homeostasis. Objective To examine…
Relationship between serum free T4 (FT4) levels and metabolic syndrome (MS) and its components in healthy euthyroid subjects
Clinical Endocrinology200829 influential citations<h4>Background</h4>The metabolic syndrome (MS) is associated with increased life-time risk for atherosclerotic cardiovascular disease. While some reports suggest that MS and/or insulin resistance is associated with low serum free T4 (FT4)…
Predictive value of free triiodothyronine (FT3) to free thyroxine (FT4) ratio in long-term outcomes of euthyroid patients with three-vessel coronary artery disease
Nutrition, Metabolism and Cardiovascular Diseases2021n=70628 influential citations<h4>Background and aims</h4>Whether routine assessment of FT3/FT4 ratio in euthyroid patients with three-vessel disease (3VD) could help identify high-risk individuals remains unclear. This study evaluated the relationship between FT3/FT4…
Effects of serum TSH and FT4 levels and the TSHR‐Asp727Glu polymorphism on bone: the Rotterdam Study
Clinical Endocrinology2007n=1,32727 influential citations<h4>Background</h4>TSH and thyroid hormone may have independent effects on bone. In this study we investigated the association of TSH and free T4 (FT4) with different bone parameters in human subjects. TSH and FT4 are known to be…
FT4 immunoassays may display a pattern during pregnancy similar to the equilibrium dialysis ID–LC/tandem MS candidate reference measurement procedure in spite of susceptibility towards binding protein alterations
Clinica Chimica Acta201026 influential citations<h4>Background</h4>Serum free thyroxine (FT4) testing in pregnancy is known to be challenging for immunoassays (IAs). We verified the reliability of FT4 results by 3 commercial IAs throughout pregnancy, by comparison of the pattern to that…
TSH enhancement of FT4 to FT3 conversion is age dependent
European Journal of Endocrinology201625 influential citationsObjective We previously reported increasing free T3 (FT3) to free T4 (FT4) ratios as thyroid-stimulating hormone (TSH) increases within the normal range in children. It is not known if this phenomenon is age-related among humans, as…
Free triiodothyronine/free thyroxine (FT3/FT4) ratio is strongly associated with insulin resistance in euthyroid and hypothyroid adults: a cross-sectional study
Endokrynologia Polska202125 influential citations<h4>Introduction</h4>Insulin resistance (IR) is a key and early pathogenetic mechanism of cardiometabolic diseases with huge potential if detected early and mitigated, for lowering the burden of the disease. Available data are conflicting…
Serum FT3/FT4, but not TSH is associated with handgrip strength in euthyroid U.S. population: evidence from NHANES
Frontiers in Endocrinology2024n=1,06725 influential citations<h4>Objective</h4>Although several studies have examined the relationship between thyroid function and muscle strength, their population primarily derived from Asian areas, and their results were controversial. Thus, this study aimed to…
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