A B C D E F G H I J K L M N O P Q R S T U V W X Y Z #

T4, FREE

Test Code
T4F


Preferred Specimen
LIGHT GREEN (LITHIUM) GEL OR GOLD TOP TUBE Tube


Specimen Stability
3 days


Clinical Significance
 In vitro diagnostic test for the quantitative determination of Free Thyroxine in human plasma used in the diagnosis and treatment of thyroid disease.  Thyroxine is synthesized the the thyroid gland and exists in circulation primarily as bound to protein.  A very small percent is unbound, or "free thyroxine" that is capable of binding to cellular receptors resulting in a physiological response.  FT4 concentrations more closely parallel thyroid dyfunction than do levels of total thyroxine.




The CPT Codes provided in this document are based on AMA guidelines and are for informational purposes only. CPT coding is the sole responsibility of the billing party. Please direct any questions regarding coding to the payor being billed. Any Profile/panel component may be ordered separately. Reflex tests are performed at an additional charge.