Laboratory Services

Thyroxine, Free (FT4)

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Updated Test Information:

Test Description
Thyroxine, Free (FT4)
Synonym(s)
FT4, Free T4
Test ID
FT4
Specimen Type
Serum
Alternate Specimen Type
Red, Li‑heparin, K2‑EDTA and K3‑EDTA plasma
Specimen Requirements
SST
Stability
5 days at 20‑25 °C,
7 days at 2‑8 °C,
30 days at ‑20 °C (± 5 °C) Freeze only once
Methodology
electrochemiluminescence immunoassay “ECLIA”
Estimated TAT
0-2 days
Testing Schedule
Monday-Saturday
CPT Code(s)
84439
Minimum Sample Volume
1 mL
Pediatric Min. Volume (if applicable)
500 uL
Reference Range
0.82-1.7 ng/dL
Performing Lab
Incyte Diagnostics
LOINC Code(s)
3024-7