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Triiodothyronine, Free (Free T3)
0070133
Ordering Recommendation

Not recommended for routine thyroid screening.

Mnemonic
FT3
Methodology
Quantitative Electrochemiluminescent Immunoassay
Performed
Sun-Sat
Reported
Within 24 hours
New York DOH Approval Status
This test is New York DOH approved.
Submit With Order
ARUP Consult®
Disease Topics
Specimen Required
Patient Preparation
 
Collect
Serum separator tube or plasma separator tube. Also acceptable: Lavender (EDTA) or pink (K2EDTA). 
Specimen Preparation
Allow specimen to clot completely at room temperature. Separate serum or plasma from cells ASAP or within 2 hours of collection. Transfer 1 mL serum or plasma to an ARUP Standard Transport Tube. (Min: 0.5 mL) 
Storage/Transport Temperature
Refrigerated. 
Unacceptable Conditions
Grossly hemolyzed specimens. 
Remarks
 
Stability
After separation from cells: Ambient: 5 days; Refrigerated: 1 week; Frozen: 1 month 
Reference Interval
0-3 days2.0-7.9 pg/mL
4-30 days2.0-5.2 pg/mL
1-24 months1.6-6.4 pg/mL
2-6 years2.0-6.0 pg/mL
7-17 years2.9-5.1 pg/mL
18 years and older2.4-4.2 pg/mL

Interpretive Data


Note
CPT Code(s)
84481
Components
Component Test Code*Component Chart NameLOINC
0070133Triiodothyronine, Free (Free T3)3051-0
* Component test codes cannot be used to order tests. The information provided here is not sufficient for interface builds; for a complete test mix, please click the sidebar link to access the Interface Map.
Aliases
  • 3, Free, Serum
  • Free T3
  • Free T3 Only, S
  • Free Triiodothyronine
  • FT3
  • T3, Free