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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