Free Thyroxine (FT4)

 

METHODOLOGY

Electrochemiluminescence Immunoassay (ECLIA)

 

PERFORMED  

 

Tuesday & Friday

REPORTED  

2 days

COLLECT  

 

One 6mL RT (Min: 4mL RT)

TRANSPORT  

 

1 mL refrigerated serum (Min: 0.5 mL)


STABILITY  


Stored at 2 - 8°C until used; Stable if frozen at - 20°C  

UNACCEPTABLE SPECIMENS  

Do not use heat-inactivated samples.


REFERENCE RANGE

 

 0.80 – 2.0 ng/dL


CPT CODE

84439


INFORMATION

 

  The thyroid hormone thyroxine (T4) is a physiologically active thyroid hormone and the principle secretory product of the thyroid gland, which has an effect on general metabolism. The major fraction of the total thyroxine is bound to transport proteins (TBG, prealbumin and albumin). The free thyroxine (FT4) moiety is the physiologically active thyroxine component. The determination of FT4 is an important test in the clinical diagnosis and treatment of thyroid disorders. 

The determination of free T4 has the advantage of being independent of changes in the concentrations and affinity of the thyroid hormone binding proteins (primarily TBG). The estimation of FT4 usually renders an additional binding protein ratio test (THBR) unnecessary.

USC ENDOCRINE SERVICES LABORATORY
126 W. Del Mar Blvd 
Pasadena, CA 91105-2508
Phone: (855) 224-7111
Fax: (855) 224-7123

Email: endolab@usc.edu

The USC Endocrine Services Laboratory is licensed by the State of California, Department of Health Services, and accredited by the College of American Pathologists, and certified by Medicare according to the provisions of the U.S. Department of Health and Human Services Clinical Laboratory Improvement Act of 1988.

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