T4, Free


Sunquest Code:FT4  
Epic Code:LAB127Epic Name:T4 Free
Synonyms:Free T4 (Thyroxine); Thyroid; FT4; TFT
Methodology:Chemiluminescence
CPT Code:84439
Turnaround Time:Varies by site.


Collection Instructions

Specimen:Blood
Optimal Volume:2.5 mL
Minimum\Peds Volume:0.6 mL
Container:Green (lithium heparin, gel) (Green (lithium heparin) on ICE, Green (sodium heparin, no gel), Green (sodium heparin, no gel) on ICE, Purple (EDTA), Purple (EDTA) on ICE, Red (no gel), Red or gold (gel))
Causes for Rejection:Gross hemolysis
Contraindications:Large doses of biotin (10 mg or more per day) may cause clinically significant interference in free T4 levels. If interference is suspected, it is strongly recommended that biotin is discontinued for at least one week prior to retesting.


Processing and Shipping

Specimen Processing:Centrifuge and aliquot 1.25 mL, 0.2 mL minimum. Store in refrigerator.
Shipping Instructions:Ship at refrigerated temperature.
Test Performed at or Referral Lab Chemistry  (University of Minnesota Health Maple Grove Clinics, Fairview Range - FRMC, UMMC-East Bank, Oxboro Bloom, Fairview Lakes - FLMC, Fairview Ridges - FRH, Fairview Northland - FNMC, Fairview Southdale - FSH, UMMC/UMMCH-West Bank, M Health Clinic and Surgery Center, Grand Itasca GICH)


Interpretive

Reference Range:
 
Male  
Age ng/dL
0-3 days 0.97-1.87
4-30 days 0.78-1.52
1 mo and older 0.76-1.46
 
Female  
Age ng/dL
0-3 days 0.93-1.44
4-30 days 0.81-1.44
1 mo and older 0.76-1.46
GICH: All ages (female and male) 0.6-1.6 ng/dL


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