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T4 Free

Last modified by  ivette_marrero  on  April 03, 2014 10:00 AM


UNC Hospitals
McLendon Clinical Laboratories
101 Manning Drive
Chapel Hill, NC 27514
Free T4; Thyroxine, Free
 
Tube Type
gold top serum separator tube
Test ID
 
FT4
EPIC Order
 
T4, FREE
CPT Code(s)
 
84439
Group/Individual Test
 
Individual 
Laboratory
 
Core Laboratory
Tube Station
 
30
Specimen
Routine:
4 mL blood/serum separator tube/gold top/red top acceptable
 
Micro:
500 ┬ÁL blood/gold or red top bullet
Availability
Routine:
24 hrs/day
 
STAT:
Yes
Turnaround Time
 
Routine: 2 hrs; STAT: 1 hr
Reference Range
Normal:
See table below
 
 
 
Comments
For additional specimen information refer to Core Laboratory Memorandum #46
Free T4 Reference Ranges (ng/dL)
Pediatric patients1
0 - 3 d
2.00-5.00
 
3 - 30 d
0.90-2.20
 
31 d - 18 y
0.80-2.00
Adults, ambulatory, healthy2
>18 y
0.71-1.40
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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