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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

Analytic Time

STAT within 1 hour upon receipt

ROUTINE within 2 hours upon receipt