Laboratory Test Information Guide

Details for Free T4, Plasma/Serum

Test Name: Free T4, Plasma/Serum
Alternate Name(s): Free Thyroxine
FT4
Laboratory: Core
Specimen Type: Adult:
4.5 mL Light Green top (Li-Heparin) Vacutainer tube

Pediatric:
0-2 years: 0.5 mL Light Green top (Li-Heparin) Microtainer
2-10 years: 3 mL Light Green top (Li-Heparin) Vacutainer tube

Red, Gold, or Lavender (EDTA) top tubes are also acceptable
Collection Information: Minimum volume of plasma or serum required is 700 ÁL for adult samples or 200 ÁL for pediatric samples.
Requisition: GENERAL LABORATORY REQUISITION
Test Schedule: As required
Turnaround time from when specimen
is received in testing laboratory:
 
Routine
4 hours
Stat
 
 
Reference Range: 0 - 6 days: 11 - 32 pmol/L
6 days - 3 months: 12 - 28 pmol/L
3 - 12 months: 12 - 26 pmol/L
1 - 6 years: 12 - 23 pmol/L
6 - 11 years: 13 - 22 pmol/L
11 - 20 years: 13 - 21 pmol/L
> 20 years: 12 - 22 pmol/L
First Trimester of Pregnancy: 12 - 20 pmol/L
Second Trimester of Pregnancy: 10 - 17 pmol/L
Third Trimester of Pregnancy: 8 - 16 pmol/L
Effective Date: 2018-03-06
Revised Date: 2018-08-17
Critical Value:  
Interpretive Comments:  
Special Processing:  
Comments: Furosemide may cause elevated free T4 results.

Biotin may interfere with this test. Samples should not be taken from patients receiving high biotin doses (i.e. > 5 mg/day) until at least 8 hours after the last biotin administration.
Method of Analysis: Roche Electrochemiluminescence
Critical Information Required:  
Storage & Shipment:  
System Codes: 
Cerner
FT4
 
Referred To:  

Questions? Comments? Contact Laura Gopaul