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Test Code FT4 T4 (Thyroxine), Free, Plasma or Serum

Methodology

Electrochemiluminescence Immunoassay Competition Assay

Performing Laboratory

Decatur Morgan Hospital-Decatur Campus/Parkway Campus

Specimen Requirements

Submit only 1 of the following specimens:

 

Plasma
Draw blood in a green-top (lithium heparin) tube(s). Spin down and send 1 mL (pediatric:  0.2 mL) of lithium heparin plasma.
Note:  1. Indicate plasma on request form.
2. Label specimen appropriately (plasma).

 

Serum
Draw blood in a plain, red-top tube(s) or a serum gel tube(s). Spin down and send 1 mL (pediatric:  0.2 mL) of serum.
Note:  1. Indicate serum on request form.
2. Label specimen appropriately (serum).

Reference Values

0.93-1.70 ng/dL

Critical values (automatic call-back) 

<50 years:  ≥7.77 ng/mL

≥50 years:  ≥6.0 ng/mL

Test Classification and CPT Coding

84439