Test Code T7 T4, T3U & FTI (T7)
Methodology
Competitive Chemiluminometric Immunoassay
Includes thyroxine (T4), triiodothyronine (T3) uptake (T3U), and free thyroxine index (FTI).
Specimen Requirements
Submit only 1 of the following specimens:
Preferred:
Serum
Serum Gel Tube
Container/Tube: Serum gel tube(s)
Specimen Volume: 2 mL (minimum volume: 1
mL) of serum-Grossly lipemic specimen is not
acceptable.
Collection Instructions: Spin down within 4 hours of draw.
Note: Label specimen appropriately (serum).
Alternate:
Serum
Plain, Red-Top Tube
Container/Tube: Plain, red-top tube(s)
Specimen Volume: 2 mL (minimum volume: 1
mL) of serum-Grossly lipemic specimen is not
acceptable.
Collection Instructions: Spin down within 4 hours of draw.
Note: Label specimen appropriately (serum).
Alternate:
Plasma
Container/Tube: Green-top (lithium heparin) tube(s)
Specimen Volume: 2 mL (minimum volume: 1 mL) of plasma-Grossly lipemic specimen is not acceptable.
Collection Instructions: Spin down within 4 hours of draw.
Note: Label specimen appropriately (plasma).
Day(s) Test Set Up
Monday through Friday
Reference Values
T4
5.5-11.0 mcg/dL
T3U
23.5%-40.6%
FTI
Males: 1.3-3.7
Females: 1.7-4.7
Performing Laboratory
Logan Health Medical Center-Chemistry
Test Classification and CPT Coding
84436-T4
84479-T3U
Specimen Transport Temperature
Refrigerate