Free Thyroxine Index

Test Information

Test Name

Free Thyroxine Index

Synonyms

FTI, Free T4 Index

Preferred Specimen

Extra SST

Testing Location

Referral

Turn Around Time

5 days

Processing Information

Registration Code

FTI

Notes

  • FTI is calculated by measuring Thyroid Uptake (TU) and multiplying by TT4

    Min. 1.0mL serum, ideally 1.5mL serum. This volume allows all total thyroid function tests to be performed.

Alternative Specimen

Heparin or Plain tube

External Referral Information

Referral Location

Canterbury Health Laboratory (via WHL)

Send Away Volume

1.0 serum/plasma

Send Away Transport

Frozen

External Lab Website

https://www.chl.co.nz/test/free-thyroxine-index-automated/