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HelpTest Code FT3 Free T3, (Triodothyronine, Free)
Performing Laboratory
Hunterdon Medical Center Laboratory
Useful For
Free T3 is helpful in diagnosing hyperthyroidism, following or in addition to TSH and Free T4 testing. (Links below) T3 is also useful for the differential diagnosis of T3 thyrotoxicosis, where only the Free T3 is abnormally elevated and the TSH depressed, while the Free T4 is within normal limits.
Specimen Required
| Container/Tube | |
| Acceptable | PST (Li Hep) Gel- Mint Green Top |
| Acceptable | SST |
| Specimen Volume | 3.0 mL |
| Minimum Volume | 1.0 mL |
Specimen Type
Plasma/Serum
Specimen Transport Temperature
Ambient
Specimen Stability
| Specimen | Temperature | Time Frame |
| Plasma | Refrigerated 2-8°C | 7 days |
| Serum-gel tube | Refrigerated 2-8°C | 7 days |
Updated June 2020
Day(s) Test Set up
Monday through Sunday
Reference Values
2.00-4.40 pg/mL
Methodology
ECLIA: Electrochemiluminescence Immunoassay
CPT Code
84481
Loinc Code
3051-9