Sign in →

T4 (Thyroxine), Total, Plasma or Serum

Performing Laboratory

Providence Alaska Medical Center

Methodology

Chemiluminescent Immunoassay

Note:  If patient’s insurance is Medicare, an Advance Beneficiary Notice of Noncoverage (ABN) may be required. See “Advance Beneficiary Notice of Noncoverage (ABN)” in “Forms” in “Special Instructions.”

Specimen Requirements

Submit only 1 of the following specimens:

 

Preferred:

Plasma

Draw blood in a light green-top (lithium heparin gel) tube(s). Spin down, separate plasma from cells, and send 1 mL (minimum volume:  0.3 mL) of lithium heparin plasma refrigerated. Avoid gross hemolysis.

Note:  1. Specimen is stable for 48 hours refrigerated.

2. Indicate plasma on request form.

3. Label specimen appropriately (plasma).

 

Alternate:

Serum

Draw blood in a gold-top serum gel tube(s). Spin down, separate serum from cells, and send 1 mL (minimum volume:  0.3 mL) of serum refrigerated. Avoid gross hemolysis.

Note:  1. Specimen is stable for 48 hours refrigerated.

2. Indicate serum on request form.

3. Label specimen appropriately (serum).

Reference Values

6.09-12.23 µg/dL

Stability

Room temp:  8 hours

Refrigerated:  48 hours

Day(s) Test Set Up

Monday through Sunday

Test Classification and CPT Coding

84436

Special Instructions