T4 (Thyroxine), Free, Serum
Method Description Describes how the test is performed and provides a method-specific reference
This is a chemiluminometric immunoassay. Free thyroxine (FT4) is measured using an automated, competitive, chemiluminescent immunoassay on the Advia: Centaur instrument. FT4 in the specimen competes with an acridinium ester-labeled analog of thyroxine (T4) for a limited amount of polyclonal rabbit anti-T4 antibody, which is covalently coupled to paramagnetic particles. An inverse relationship exists between the amount of FT4 in the patient specimen and the amount of relative light units detected by the system.(Package insert: Bayer Advia: Centaur. Bayer Diagnostics. East Walpole, MA)
Day(s) and Time(s) Test Performed Outlines the days and times the test is performed. This field reflects the day and time the sample must be in the testing laboratory to begin the testing process and includes any specimen preparation and processing time required before the test is performed. Some tests are listed as continuously performed, which means assays are performed several times during the day.
Monday through Friday, Sunday; 6 a.m.-3 p.m.