THYROID PROFILE (T7)/FREE THYROXINE INDEX (FTI)

Test Documentation
Components
Includes T3 (Triiodothyronine) Uptake, and T4 (Thyroxine), Total, plus Free thyroxine Index calculation.

Specimen Required
Draw blood in a SST. Centrifuge, separate and send 1.0 mL serum (0.5 mL minimum) refrigerated in a screw-capped plastic vial.

Alternate Specimen
Serum: Red-top

Rejection Criteria
Grossly hemolyzed or lipemic specimens, plasma

Methodology
Chemiluminescence

Stability
Room Temperature: 8 hours; Refrigerated: 72 hours; Frozen: 14 days

Reference Range
23-37%   T3 (Triidothyronine) Uptake  
4.5-10.9 µg/dL   T4 (Thyroxine), Total  
1.4-3.1   Free Thyroxine Index (FTI)  

Performed
Monday-Friday

Turnaround Time1-2 days
Test CodeFTI
CPT-4 Code (s)
84436, 84479
LOINC Codes
T3 (Triiodothyronine) Uptake   3050-2  
T4 (Thyroxine), Total   3026-2  
Free Thyroxine Index (FTI)   32215-6  

Warde
Medical
Laboratory