Free Triiodothyronine(FT3) CLIA kit (Chemiluminescence Immunoassay) is an in vitro diagnostic quantitative test kit. In individuals with normal thyroid function, as the concentrations of the carrier proteins change, the total T3 levels also change so that the free triiodothyronine (fT3) concentration

remains constant. Thus, measurements of fT3 concentrations correlate more reliably with clinical status than total triiodothyronine levels.