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Specimen Collection Manual and Test Catalog

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T3, FREE

Geisinger Epic Procedure Code:  LAB3123    Geisinger Epic ID:  7038

SPECIMEN COLLECTION
Specimen type: 

Plasma or Serum


Specimen required: 

2 mL of serum or plasma; minimum 0.5 mL.



SPECIMEN PROCESSING
Processing instructions: 

Allow serum to clot. Centrifuge to separate serum or plasma within 2 hours of collection.


Transport temperature: 

Refrigerated (preferred) or frozen.


Specimen stability: 

Refrigerated: 7 days. Frozen: 1 month.


Rejection criteria: 

Stability limits exceeded.



TEST DETAILS
Reference interval: 

2.5 - 4.3 pg/mL


CPT code(s):  84481
Note: The billing party has sole responsibility for CPT coding.  Any questions regarding coding should be directed to the payer being billed.
The CPT codes provided by GML are based on AMA guidelines and are for informational purposes only.

Test includes: 

Free triiodothyronine.


Methodology: 
Electrochemiluminescence
Synonyms: 

Free T3, FT3, FREET3, Free triiodothyronine


Clinical significance: 

This test is used to diagnose hyperthyroidism and to clarify thyroid status in the presence of possible protein binding abnormality.


Doctoral Director(s): 
Hoi-Ying Elsie Yu, PhD, DABCC, FADLM
Sheng-Ying (Margaret) Lo, PhD, DABCC
Review Date:  12/27/2024

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