Free Thyroxine Index : 1003551

Test Code
FTIB or 1003551

Alias/See Also
FTI; T7; Free Thyroxine calculation

CPT Codes
84436, 84479

Includes
Panel includes: Total T4, T Uptake, and calculated Free Thyroxine Index (FTI).

Instructions
Serum separator tube (gold top preferred), plain red top tube.

Transport Container
Centrifuge the serum separator tube and transport; if a plain red top tube, centrifuge and aliquot serum (Min. 0.4 mL) into a standard transport tube.

Transport Temperature
Refrigerated.

Specimen Stability
After separation from cells: Ambient: 8 hours; Refrigerated: 7 days; Frozen: Acceptable for longer storage

Reject Criteria (Eg, hemolysis? Lipemia? Thaw/Other?)
Not refrigerated within 8 hours

Methodology
Immunoassay using chemiluminescence

Setup Schedule
Sunday - Saturday

Report Available
1 day

Reference Range
T4: 4.5 - 10.9 mg/dL

T Uptake: 22.5 - 37.0 %

FTI: 1.7 - 4.2

Clinical Significance
T4 and T-Uptake are used for calculation of Free Thyroxine compensating for abnormal binding proteins.

Performing Laboratory
med fusion



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.