Free Thyroxine

Also known as: Free T4, FT4

Specimen requirements

Adult sample type: Serum (gold/yellow top SST)

Paediatric sample type: Plasma (orange top paediatric tube)

Collection requirements: No special requirements

Cost

Price on application

Turnaround time

Please see Turnaround times

Analytical method

Immunoassay - Indirect / Competitive

Analysis undertaken at these site(s)

• John Radcliffe Hospital
• Horton General Hospital

Reference intervals

Female

<1 year: 11.0 - 23.6 pmol/L
1 - 5 years: 11.7 - 20.8 pmol/L
6 - 10 years: 10.9 - 19.0 pmol/L
11 - 14 years: 10.0 - 17.0 pmol/L
15 - 19 years: 10.2 - 17.3 pmol/L
> 19 years: 9.0 - 19.0 pmol/L

Male

<1 year: 11.0 - 23.6 pmol/L
1 - 5 years: 11.7 - 20.8 pmol/L
6 - 10 years: 10.9 - 19.0 pmol/L
11 - 14 years: 10.0 - 17.0 pmol/L
15 - 19 years: 10.2 - 17.3 pmol/L
> 19 years: 9.0 - 19.0 pmol/L