Test Code FT3 T3, Free, LAB137
Methodology
Chemiluminescence Immunoassay
Performing Laboratory
St. Luke's Hospital Cedar Rapids
Specimen Requirements
Container/Tube:
Preferred: Green-top (lithium heparin) tube
Acceptable: Gold-top serum gel tube or plain, red-top tube, EDTA lavendar
Specimen Volume: 0.5 mL of plasma or serum
Stability: 7 days when separated from cells at 2 – 8 °C
Note: This assay is affected by biotin interference.
Reference Values
Age Group |
Free T3 |
Neonates 0 – 29 days |
1.8 – 7.7 pg/mL |
Infants 1 – 23 months |
3.3 – 5.2 pg/mL |
Children 2 years – 12 years |
3.3 – 4.9 pg/mL |
Adolescents 13 years – 20 years |
2.9 – 4.5 pg/mL |
Adults ≥21 years |
2.2 – 4.0 pg/mL |
Day(s) Test Set Up
Monday through Sunday
Test Classification and CPT Coding
84481
Useful For
Thyroid function
Report Available
STAT within 1 hour upon receipt
ROUTINE within 2 hours upon receipt