Test ID: T4TF
T4 (Thyroxine), Total and Free
Useful For 
Suggests clinical disorders or settings where the test may be helpful
See individual test descriptions for:
-T4/8724 T4 (Thyroxine), Total Only, Serum
-FRT4/8725 T4 (Thyroxine), Free, Serum
Clinical Information Discusses physiology, pathophysiology, and general clinical aspects, as they relate to a laboratory test
See individual test descriptions for:
-T4/8724 T4 (Thyroxine), Total Only, Serum
-FRT4/8725 T4 (Thyroxine), Free, Serum
Reference Values Describes reference intervals and additional information for interpretation of test results. May include intervals based on age and sex when appropriate. Intervals are Mayo-derived, unless otherwise designated. If an interpretive report is provided, the reference value field will state this.
T4 (THYROXINE), TOTAL ONLY
> or =12 months: 5.0-12.5 mcg/dL
Reference values have not been established for patients that are <12 months of age.
T4 (THYROXINE), FREE
0.8-1.8 ng/dL
Elevated values are seen in patients on thyroxine therapy.
Interpretation Provides information to assist in interpretation of the test results
See individual test descriptions for:
-T4/8724 T4 (Thyroxine), Total Only, Serum
-FRT4/8725 T4 (Thyroxine), Free, Serum
Cautions Discusses conditions that may cause diagnostic confusion, including improper specimen collection and handling, inappropriate test selection, and interfering substances
See individual test descriptions for:
-T4/8724 T4 (Thyroxine), Total Only, Serum
-FRT4/8725 T4 (Thyroxine), Free, Serum
Clinical Reference Provides recommendations for further in-depth reading of a clinical nature
See individual test descriptions for:
-T4/8724 T4 (Thyroxine), Total Only, Serum
-FRT4/8725 T4 (Thyroxine), Free, Serum
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