Thyroxine, Free by Equilibrium Dialysis

Label Mnemonic:	FT4D
Epic code:	LAB3177

Commercial Mailout Laboratory
6240-8 RCP
356-8593

Specimen(s):

Serum

Specimen Instructions:

Separate from cells or gel ASAP or within 2 hours of collection.

Collection Medium:

Red top tube 5 mL (Clot Activator)

Minimum:

Preferred Minimum: 2 mL serum
Absolute Minimum: 0.3 mL serum

Rejection Criteria:

Serum separator tubes and gels.

Turn Around Time:

2-5 days upon receipt at reference laboratory

Reference Range:

                         Free Thyroxine ng/dL
          Age                   Female            Male 
25-30 weeks gestation:      0.5-3.3 ng/dL    0.5-3.3 ng/dL 
31-36 weeks gestation:      1.3-4.7 ng/dL    1.3-4.7 ng/dL 
Birth to 1 week:            2.2-5.3 ng/dL    2.2-5.3 ng/dL 
2-3 weeks:                  0.9-4.0 ng/dL    0.9-4.0 ng/dL 
1-5 months:                 1.1-2.2 ng/dL    1.1-2.2 ng/dL 
6 months- 6 years:          1.4-2.7 ng/dL    1.4-2.7 ng/dL 
7 years- 17 years:          1.1-2.0 ng/dL    1.1-2.0 ng/dL 
18 years and older:         1.1-2.4 ng/dL    1.1-2.4 ng/dL 
Pregnancy, 1st Trimester    0.7-2.0 ng/dL  
Pregnancy, 2nd Trimester    0.7-2.1 ng/dL  
Pregnancy, 3rd Trimester    0.5-1.6 ng/dL

Methodology:

Quantitative Equilibrium Dialysis/High Performance Liquid Chromatography-Tandem Mass Spectrometry

CPT Code:

84439