T4, Free

Abbrev Code:FT4   
Order Code:LAB127Order Name:T4 Free
Synonyms:Free T4 (Thyroxine); FT4
CPT Codes: 84439 x1
Turnaround Time:Varies by site.

Collection Instructions

Optimal Volume:2.5 mL
Minimum\Peds Volume:0.6 mL
Container:Green (lithium heparin, gel)
Alternate Containers: 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.
Stability:Stability: Room temperature - 24 hours; refrigerated - 14 days; frozen - 3 months,
Test Performed at or Referral Lab Chemistry  (University of Minnesota Health Maple Grove Clinics, Range, UMMC-East Bank, Oxboro Bloom, Lakes, Ridges, Northland, Southdale, UMMC/UMMCH-West Bank, M Health Clinic and Surgery Center, Grand Itasca)


Reference Range:
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
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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