Test Directory
4226 T4 (Thyroxine), Free
Specimen Type
Specimen Stability
Reference Range
Serum-SST
7 days 2-8° C
0.89-1.76 ng/dL
Specimen Requirements
Preferred amount: 1.0 mL Serum
Minimum amount: 0.5 mL Serum
Minimum amount: 0.5 mL Serum
Method
Immunochemiluminometric
Schedule
Mon-Sat
Turn-Around Time
24hrs; Also offered STAT at an additional charge
Instructions/Notes
Centrifuge required?: Yes
Clinical Utility
In combination with T3 Uptake, T4 is used to help evaluate thyroid gland function; to help diagnose hypothyroidism or hyperthyroidism. T4 is also used to screen for hypothyroidism in newborns.
CPT Codes
84439
