3230 Thyroxine, Free Index

Components
NAME METHOD REFERENCE RANGE UNITS
T Uptake ICMA  25 - 35  % 
Thyroxine (T4) ICMA  view ref range  ug/dL 
Free Thyroxine Index CALC  1.1 - 4.2   


Specimen Requirements
TYPE VOLUME TEMPERATURE INSTRUCTIONS
PRIMARY
1 Serum 2 (1) mL   Refrigerated - 4 Day(s), Frozen - 2 Month(s)  


Clinical utility
Thyroid function tests to diagnose hypothyroidism or hyperthyroidism. TSH and free T4 are recommended for assessment of thyroid function. Indirect index methods employ two separate tests to estimate the free hormone concentration: total serum T4 (or T3) measurement and an assessment of either TBG or the free hormone fraction. Results of these tests are then combined mathematically to give estimates of the free hormone concentration.


Reported: Same day

CPT Code: 84436, 84479

Notes: Also known as Free T4 Index.