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Test Code FT3 T3 (Triiodothyronine), Free

Important Note

Patients taking high doses of Biotin may have false elevated FT3 levels.

Performing Laboratory

Memorial Hospital Laboratory- Automated Procedures  304-388-5953       
Teays Valley Hospital Laboratory 304-757-1770
Greenbrier Valley Laboratory 304-647-6060

Specimen Requirements

Memorial, Teays

Plasma-Mint Green, Dark Green Lithium Heparin or Serum-SST gold top, red top

Allow SST or red top to completely clot

Spin and physically separate plasma/serum from contact with cells as soon as possible

4 mL of plasma/serum (minimum 2 mL)

 

Greenbrier

Heparin Plasma, Serum or EDTA plasma

Allow SST or red top to completely clot

Spin and physically separate plasma/serum from contact with cells as soon as possible

4 mL of plasma/serum (minimum 2 mL)

Specimen Rejection

  • Improperly labeled, collected, stored, and transported
  • Quantity not sufficient

Additional rejections at Greenbrier only

  • Turbid
  • Hemolyzed
  • Lipemic

Storage and Stability

Memorial, Teays 

Room temperature 15-30oC 8 hrs
Refrigerated 2-8oC 48 hrs
Frozen <-20oC Not specified

 

Greenbrier 

Refrigerated 2-8oC 7 days
Frozen <-20oC 4 weeks

Reference Values

Memorial, Teays 

Age Range Reference Range (pg/mL)
0 minutes - 18 yrs 2.8 - 4.4
18 yrs - 150 yrs 2.5 - 3.9

 

Greenbrier 

Age Range Reference Range (pg/mL)
<18 yrs 2.8 - 4.4
>18 yrs 2.5 - 3.9

Methodology

Memorial, Teays-Chemiluminescent  immunoenzymatic competitive assay

Greenbrier-Competitive immunoassay

 

Days Test Set Up and Turnaround

Monday through Sunday, Continuously

AM Collection Expected by 9AM same day
Routine Expected within 24 hrs
Stat Expected within 1 hr
Timed Expected results are test dependant

CPT Coding

84481