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 #

Free Thyroxine (Free T4)

Test Code
T4F


CPT Codes
84439

Preferred Specimen
SST Serum Separator


Minimum Volume
0.50 mL


Other Acceptable Specimens
Red No Gel


Transport Container
SST Serum Separator


Transport Temperature
Room Temperature


Specimen Stability
Refrigerated: 7 Days


Reject Criteria (Eg, hemolysis? Lipemia? Thaw/Other?)
Gross hemolysis


Methodology
Vitros 7600

Clinical Significance
The free fraction of the circulating thyroxine (T4) is considered to exert the main influence on metabolic control. Consequently, the FT4 concentration is believed to be the most direct indicator of an individual’s thyroid status. FT4
concentrations are generally depressed in hypothyroidism and raised in hyperthyroidism. Measurement of FT4 thus
provides an aid to the differential diagnosis of thyroid disease.


Performed By
RFGH Laboratory

Performing Laboratory
RFGH Laboratory



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.