| Description | ThefT4ELISAkitisusedforthequantitativemeasurementoffreeThyroxine(fT4)inhumanserumorplasma.Over99%ofthyroxine(T4)circulatesinbloodisboundtocarrierproteins;thyroxine-bindingglobulin(TBG).However,onlythefree(unbound)portionofThyroxineisresponsibleforthebiologicalaction.Further,theconcentrationsofthecarrierproteinsarealteredinmanyclinicalconditions,suchaspregnancy.Innormalthyroidfunctionastheconcentrationsofthecarrierproteinsalters,thetotalT4levelchangessothatthefreeT4concentrationremainsconstant.Thus,measurementsoffreeT4concentrationscorrelatemorereliablywithclinicalstatusthantotalT4levels.TheincreaseintotalT4levelsassociatedwithpregnancy,oralcontraceptivesandestrogentherapyresultinhighertotalT4levelswhilethefreeT4concentrationremainsbasicallyunchanged. |
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| Species | Human |
| SampleType | SerumorPlasma |
| Name | FreeThyroxine(FT4)ELISA |
|---|---|
| ShortDescription | ThefT4ELISAkitisusedforthequantitativemeasurementoffreeThyroxine(fT4)inhumanserumorplasma.Over99%ofthyroxine(T4)circulatesinbloodisboundtocarrierproteins;thyroxine-bindingglobulin(TBG).However,onlythefree(unbound)portionofThyroxineisresponsibleforthebiologicalaction.Further,theconcentrationsofthecarrierproteinsarealteredinmanyclinicalconditions,suchaspregnancy.Innormalthyroidfunctionastheconcentrationsofthecarrierproteinsalters,thetotalT4levelchangessothatthefreeT4concentrationremainsconstant.Thus,measurementsoffreeT4concentrationscorrelatemorereliablywithclinicalstatusthantotalT4levels.TheincreaseintotalT4levelsassociatedwithpregnancy,oralcontraceptivesandestrogentherapyresultinhighertotalT4levelswhilethefreeT4concentrationremainsbasicallyunchanged. |
| Reactivity | Human |