Ikhithi isetshenziselwa ukutholwa kwe-in vitro quantitative yengqikithi ye-thyroxine (TT4) ku-serum yomuntu, i-plasma noma amasampula egazi lonke.
Ikhithi isetshenziselwa ukuthola ngobuningi ukugcwala kwe-triiodothyronine (TT3) ku-serum yomuntu, i-plasma noma amasampula egazi lonke ku-vitro.
Ikhithi isetshenziselwa ukutholwa kwenani lokuhlangana kwehomoni evuselela igilo (TSH) ku-serum yomuntu, i-plasma noma amasampula egazi lonke ku-vitro.