Home
HelpTest Code T4 T4 (Thyroxine), Serum
Specimen Requirements
Draw blood in a plain, red-top tube(s) or a serum gel tube(s). Spin down and send 1 mL of serum refrigerated.
Gold or green SST
Specimen Stability
Stable
Refrigerated - 7 days
Frozen - 30 days
Performing Laboratory
Conway Regional Clinical Laboratory Services
Reference Values
T4
5.0-12.0 µg/dL
hypothyroid <5.0
euthyroid 5-12
hyperthyroid 11.7
Note: For a more reliable measurement of thyroxine, order #FRT4 “T4 (Thyroxine), Free, Serum.”
Methodology
Electrochemluminescence
Day(s) Test Set Up
Monday through Sunday
Available STAT
Test Classification and CPT Coding
84436