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Free T4; Thyroxine, Free; T4, Free

Last modified by  mike_rogers  on  February 09, 2010 10:16 PM


UNC Hospitals
McLendon Clinical Laboratories
101 Manning Drive
Chapel Hill, NC 27514

 

Tube Type
gold top serum separator tube

Test ID FT4
Test Number 706
SMS Browse T4 FREE
FREE T4
CPT Code(s) 84439
Group/Individual Test Individual 
Laboratory Core Laboratory
Tube Station 30
SpecimenRoutine:4 mL blood/Serum Separator Tube/Gold Top
 Micro: 2 microtainers/900 µL blood
AvailabilityRoutine:

24 hours/day

 STAT:Yes
Turnaround Time Routine: 2 hours
STAT: 1 hour
Reference RangeNormal:0.71 - 1.40 ng/dL, ambulatory adults.
See table below for other populations.
Comments

For additional specimen information refer to Core Laboratory Memorandum #46

Free T4 Reference Ranges (ng/dL)
Pediatric patients1
 0 - 3 d2.00-5.00
 3 - 30 d0.90-2.20
 31 d - 18 y0.80-2.00
   
Adults, ambulatory, healthy2 >18 y0.71-1.40
Pregnant, euthyroid patients3  Levels trend 23-38% lower than the reference mean. The lowest point typically occurs ~34-36 w.

1. Dugaw KA, Jack RM, Rutledge J Pediatric reference ranges for TSH, free T4, total T4, total T3, and T3 Uptake on the Vitros ECi analyzer. Clin Chem 2001; 47: A108.
2. Reference range determined in-house
3. Lockitch G. Handbook of Diagnostic Biochemistry and Hematology in Normal Pregnancy. CRC Press. 1993.

 

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 Free T4; Thyroxine, Free; T4, Free

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