Alert

T3 Free

Tube Type

Free T3

Test ID

LAB137

EPIC Order
T3, FREE
CPT Code(s) 84481
Group/Individual Test Individual
Laboratory Core Laboratory
Tube Station 30
Specimen Routine: 4 mL blood/serum separator tube/gold top/red top acceptable
Micro: 0.9 mL blood/gold or red top bullet;
Stability
Unspun: 4 hours
Spun/separated, Room Temperature: </=4 hrs recommended
Spun/separated, Refrigerator: 7 days
Spun/separated, Frozen: 28 days
Availability Routine: 24 hrs/7 days
STAT: Yes
Turnaround Time 2 hrs
Reference Range and
Interpretation

Euthyroid patients
Age Group (years)
Free T3 Reference range (pg/mL)
(effective 8/5/2011)
<20 2.28-4.81
20-39 2.32-6.09
40-59 2.71-6.16
60-79 2.45-5.93
>79 2.34-5.61
Reference Range and
Interpretation

(effective 8/5/2011)

Euthyroid pregnant women
Trimester
Free T3 Reference range (pg/mL)
(effective 8/5/2011)
First 2.88-4.32
Second 2.56-4.41
Third 2.47-4.73
Comments

See Core Laboratory numbered Memo #99  

Thyroid hormone autoantibodies in serum samples may cause interference in free-hormone immunoassays.  Heterophilic antibodies may cause test interference.

Reviewed by jcarr on December 16, 2019

Note: Reference ranges provided on this web site are for guidance only, and may not reflect the most recent changes. Refer to laboratory reports for current reference data.

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

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