Indicator Explainer
Thyroxine
A hormone synthesized and secreted by the thyroid gland containing four iodine atoms and is converted to triiodothyronine (T3) in the body, influencing metabolism and organ function.
This page explains what the indicator is and how results are interpreted in general terms. Reference ranges depend on the laboratory, the method, and your own situation — no single “normal value” applies to everyone. This page is health information, not a diagnosis. For symptoms, treatment, or urgent concerns, contact a healthcare professional.
When it is tested
Source: National Cancer Institute, NCI Thesaurus 26.09d, C2302. NCI definition, reproduced without modification under CC BY 4.0. Source identity and definition checked automatically on 2026-10-18. No individual clinical interpretation or human reviewer is asserted.
Reading results
Reference intervals and interpretation depend on the laboratory, specimen, method and clinical context. This source definition is educational information; it does not establish a diagnosis, product approval or suitability for an individual.
Also Known As
References
- NCI Thesaurus 26.09d — Thyroxine (C2302)
- Source: National Cancer Institute, NCI Thesaurus 26.09d, C2302. NCI definition, reproduced without modification under CC BY 4.0.
- The transient pubertal free thyroxine dip should not be misinterpreted as central hypothyroidism: a case series. — Horm Res Paediatr, 2026-10-01 (PMID 42821490; literature)
- Levothyroxine Administration in Intensive Care Unit Patients with Low Thyroxine Levels: A Retrospective Comparison Study. — Horm Metab Res, 2026-09-29 (PMID 42810385; literature)