Thyroxine, Free (FT4)
Free T4 regulate normal growth and development by maintaining body temperature and stimulating calorigenesis. In addition, free T4 affect all aspects of carbohydrate metabolism as well as certain areas of lipid and vitamin metabolism. Clearly elevated free T4 levels support the clinical findings of a diagnosis of hyperthyroidism while clearly low free T4 levels coupled with appropriate clinical findings, can establish a diagnosis of hypothyroidism.
1 mL Serum Refrigerated
Turn Around Time
Chemiluminescent immunoassay (CLIA)
Non-thyrometabolic disorders may cause abnormal free T4 levels, Anticonvulsant drug therapy (particularly phenytoin) may result in decreased free T4 levels and patients on heparin therapy may have elevated free T4 levels.