Free Triiodothyronine (FT3)
Free T3
Testing Information
Sample Type
Serum
Test Codes
630220
CPT Code
84481
Testing Area
Core Lab - Chemistry
Test Methodology
Abbott Alinity - Chemiluminescence Immunoassay
Reference Range
1.6-3.9 pg/mL
Expected Turnaround Time
Results Available 24 hours from Receipt
Specimen Collection Criteria
Collect one gold top SST tube (minimum whole blood: 4 mL). Let specimen clot for 30-60 minutes and then centrifuge to separate serum from cells. Refrigerate after centrifugation.
Rejection Criteria
Grossly hemolyzed specimens, quantity not sufficient, improperly labeled
Specimen Validity and Retention
Centrifuged SST Tubes:Room Temperature (20-25°C): 2-4 hoursRefrigerated (2-8°C): 7 daysFrozen (-20°C or greater): UnacceptableSerum Aliquots:Room Temperature (20-25°C): 2-4 hoursRefrigerated (2-8°C): 7 daysFrozen (-20°C or greater): 7 daysSpecimens retained for 7 days after testing
Courier Transportation
Transport centrifuged tube refrigerated (2-8°C)
Clinical Utility
Free T3 assays are useful in measurement of thyroid function and abnormal binding protein disorders.
Special Notes
Stop Biotin supplements?
