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