Test Catalog

Test ID: TBGI    
Thyroxine-Binding Globulin (TBG), Serum

Method Description Describes how the test is performed and provides a method-specific reference

The IMMULITE 2000 TBG (thyroxine-binding globulin) is a solid-phase chemiluminescent immunoassay. The solid phase, a polystyrene bead, is coated with a monoclonal antibody specific for TBG. The patient sample and alkaline phosphate-conjugated TBG are added and incubated. During this time, TBG in the sample competes with the enzyme-labeled TBG for a limited number of antibody binding sites on the bead. Unbound enzyme conjugate is removed by washing and the chemiluminescent substrate is added. The substrate, a phosphate ester of adamantyl dixetane, undergoes hydrolysis in the presence of alkaline phosphatase to yield an unstable intermediate. The continuous production of the intermediate results in the sustained emission of light. The photon output is inversely proportional to the concentration of the TBG in the sample.(Package insert: IMMULITE 2000 TBG PIL2KTB-16. Siemens Medical Solutions; 07/29/2008)

PDF Report Indicates whether the report includes an additional document with charts, images or other enriched information


Day(s) Performed Outlines the days the test is performed. This field reflects the day that the sample must be in the testing laboratory to begin the testing process and includes any specimen preparation and processing time before the test is performed. Some tests are listed as continuously performed, which means that assays are performed multiple times during the day.

Monday, Wednesday, Friday

Report Available The interval of time (receipt of sample at Mayo Clinic Laboratories to results available) taking into account standard setup days and weekends. The first day is the time that it typically takes for a result to be available. The last day is the time it might take, accounting for any necessary repeated testing.

Same day/1 to 3 days

Specimen Retention Time Outlines the length of time after testing that a specimen is kept in the laboratory before it is discarded

3 months

Performing Laboratory Location Indicates the location of the laboratory that performs the test