Triiodothyronine, Free

Alternative Names/Synonyms	Free T3, FT3
Laboratory	Core Laboratory & Transfusion Medicine
Sub-section	Biochemistry
Specimen Type	Blood
Test Code	FT3S3, FT3P3

Clinical Significance

Assisting in the diagnosis of primary and secondary thyroid function disorders, non-thyroidal illness and TSH-resistance syndrome.

Monitoring response to therapy in hyperthyroid or thyroid cancer patients.

Specimen Requirements (Sample Type)

Serum, Plasma

Specimen Requirements (Volume (mL))

0.5 mL

Specimen Requirements (Tube Type)

Serum (Gold SST)
Plasma (Light Green PST)
Collection Containers – Tube Types

Collection Requirements

Blood Collection Instructions

Sample Stability

Room Temperature: 24 hours

Fridge: 7 days @ 2-8°C

Freezer: 1 year @ -20°C

Cause for Rejection

Specimen Acceptability and Transport Guidance

Instrument, Methodology

Roche cobas e 602, immunoassay

Test Availability

24 hours a day, 7 days a week

STAT Turnaround Time

1 hour

Routine Turnaround Time

3 hours

Reference Ranges

4.6 - 6.8 pmol/L

In case of discrepancies, always interpret results using reference ranges as stated on laboratory reports and/or electronic patient chart.

Laboratory Contact Information

416-586-4800 extension 4688