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HelpTest Code FRT3 T3 (Triiodothyronine) Free, Plasma or Serum
Performing Laboratory
Bronson Laboratory Services-Chemistry
Reference Values
2.57-4.43 pg/mL
Methodology
Chemiluminescent Immunoassay
This test is recommended over total T3 because the free
T3
represents the physiologically active hormone rather than the
quantity of carrier proteins.
Specimen Requirements & Patient Preparation
Patient Preparation: For 12 hours before this test do not take multivitamins or dietary supplements containing biotin (vitamin B7), which is commonly found in hair, skin, and nail supplements and multivitamins. Biotin can interfere with many immunoassay tests.
Submit only 1 of the following specimens:
Preferred
Specimen Type: Serum
Container/Tube: Gold or Red
Specimen Volume: 5 mL
Specimen Minimum Volume: 1 mL
Alternative
Specimen Type: Plasma
Container/Tube: Mint or Green
Specimen Volume: 5 mL
Specimen Minimum Volume: 1 mL
Specimen Transport Temperature
Refrigerate
Day(s) Test Set Up
Monday through Sunday
Test Classification and CPT Coding
84481
Specimen Stability
Refrigerated - 7 days
Frozen - 1 month