Free T4
Thyroxine is also called T4. T4 is a hormone that your thyroid gland makes. A T4 test measures the level of T4 in a sample of your blood. Too much or too little T4 may be a sign of a thyroid problem.
A T4 test is usually used with other thyroid tests to help diagnose and monitor thyroid disease and to gather more information about other conditions that may affect your thyroid.
Source: MedlinePlus, U.S. National Library of Medicine
Normal range
No published reference range from a named lab yet.
What an abnormal result can be associated with
- A high result
- Increased circulating T4 concentration
- A low result
- Decreased circulating T4 concentration
Associations from LOINC2HPO (Human Phenotype Ontology). This is reference information, not a diagnosis — only a clinician can interpret your result in context.
Details
- Sample
- Serum or plasma · LOINC
- Monitored for
- Hypothyroidism
- Listed under
- Hyperthyroidism · Thyroid Diseases
- Code
- LOINC 3024-7 · ng/dL
- Also known as
- Thyroxine (T4) free, Non-protein bound, Levo-thyroxine, T4 Free, T4