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HelpTest Code FRT4 T4 (Thyroxine), Free, 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.
Specimen Stability
Stable for:
Refrigerated - 7 days
Frozen - 30 days
Performing Laboratory
Conway Regional Clinical Laboratory Services
Reference Values
Euthyroid: 0.93-1.7 ng/dL
Hypothyroid: <0..93 ng/dL
Hyperthyroid: >1.7 ng/dL
Note: Elevated results are seen in patients on thyroxine therapy.
Methodology
Electrochemluminescence
Day(s) Test Set Up
Monday through Sunday
Available STAT
Test Classification and CPT Coding
84439