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Test Code LAB4200 FREE T4 (FREE THYROXINE)

Important Note

Use same specimen type for serial measurements.

Specimen Type

Preferred Sample: Lithium Heparin Plasma (Mint Green Top)
Alternative Sample: Serum (SST, Gold, Corvac, Tiger, Red Top Tube)

Specimen Volume

1 mL

Minimum Volume

0.5 mL

Microtainer - 0.2 mL

Turnaround Time

STAT: 1 hour
Routine: 4 hours

Test Schedule

Daily

Sample Stability

Refrigerated: 6 days
 

 

Method

Immunoassay

Reference Ranges

Adult Reference Range: 0.70-1.48 ng/dL

Critical Values: None

Age specific reference range:

Age Range
    0 up to 1 Years 0.81-1.46 ng/dL
1 Years up to 19 Years 0.77-1.11 ng/dL

 

Reporting Limit

Measuring Range: 0.42-5.00 ng/dL

Reporting Range: 0.42-5.00 ng/dL

Synonyms

THYROXINE, THYROID, HORMONE, FT4, FREE T4, LAB4200, FREE T4, DIRECT, FREE THYROXINE, UNBOUND T4, DIRECT T4

CPT Codes

84439