ARUP's Laboratory Test Directory

Thyroxine, Free by Equilibrium Dialysis/HPLC-Tandem Mass Spectrometry : 0093244

Mnemonic: FT4 ED-TMS

Methodology: Equilibrium Dialysis/High Performance Liquid Chromatography-Tandem Mass Spectrometry
Performed: Mon-Fri
Reported: 2-5 days
Specimen Required: Collect:  One 5 mL plain red.

Storage/Transport Temperature:  2 mL serum at 2-8°C. (Min: 0.5 mL) Submit specimen in an ARUP Standard Transport Tube.

Remarks:  Avoid use of serum separator tubes and gels.

Stability (collection to initiation of testing):  After separation from cells: Ambient: 4 days; Refrigerated: 2 weeks; Frozen: 1 month
Reference Interval:
 
Age Thyroxine ng/dL
25-30 weeks gestation:
31-36 weeks gestation:
Birth to 1 week:
2-3 weeks:
1-11 months:
12 months - 18 years:
19 years and older: 		0.5-3.3 ng/dL
1.3-4.7 ng/dL
2.2-5.3 ng/dL
0.9-4.0 ng/dL
1.1-2.2 ng/dL
1.0-2.0 ng/dL
1.1-2.4 ng/dL
Pregnancy:
1st Trimester:
2nd Trimester:
3rd Trimester: 		Pregnancy:
0.7-2.0 ng/dL
0.7-2.1 ng/dL
0.5-1.6 ng/dL

CPT Code(s): 84439
Cross References: T4, Free, Equilibrium Dialysis
 
 

 

 

 
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