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ID:199 Thyroxine (free thyroxine, fT4)
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DescriptionCirculating thyroid hormone
IndicationInvestigation of thyroid function and monitoring of treatment.
Additional InfoN.B Both serum and heparin plasma samples are acceptable.THYROID FUNCTION TESTS ARE STABLE FOR UP TO 72 HOURS.
Concurrent Testsna
Dietary Requirementsna
InterpretationfT4 and TSH are the first line screening tests in the investigation of thyroid dysfunction. The results should be interpreted together.

TubeSerum or Heparin
Tube Picture
Collection Conditions
Min. Vol1 mL

Ref. Range (Male)10 - 20
Ref. Range (Female)10 - 20
Ref. Range (Paed)
Ref. Range Notes
IP Acute TAT1.5 hours
IP Routine TAT3 hours
GP Acute TAT- Contact Laboratory
GP Routine TAT24 hours
Turnround CommentMinimum re-test interval = 28 days

Originally edited by : JHB. Review due on 04/12/2015 16:13:42. Published By dan carless on 04/12/2014 16:13:42.