Free T3
Abbreviation
FT3
Preferred Specimen
Serum
Minimum Volume
0.5mL
Collection Instructions
Routine venipuncture
Transport Container
Draw tube or plastic pour off tube
Transport Temp
Frozen
Stability
- 2-8 C for 24 hours
- -20C up to 12 months
Methodology
CLIA (chemiluminescent immunoassay)
Reference Ranges
- Normal range: 2.2-4.2 pg/mL
Clinical Significance
To identify patients with thyrotoxicosis whose T4 and FT4 concentrations are normal, while T3 is elevated. FT3 is useful to identify subclinical hyperthyroidism with suppressed TSH, and nnormal Ft4 and FT3 levels.