Test Catalog

Test ID: HTGFN    
Thyroglobulin, Tumor Marker, Fine-Needle Aspiration (FNA)-Needle Wash, Lymph Node

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

For Mayo Clinic patients, any visibly blood-tinged samples are spun in a clinical centrifuge, and the supernatant is used for testing. If there is no visible blood contamination, the sample is used directly. Mayo Clinic Laboratories specimens should be evaluated for hemolysis before submission.


The saline needle-wash specimen is analyzed with the Beckman Access thyroglobulin (Tg) assay, a simultaneous 1-step immunoenzymatic (sandwich) assay performed on the Beckman Coulter UniCel DxI 800. A sample is added to a reaction vessel along with a biotinylated mixture of 4 mouse monoclonal anti-Tg antibodies, streptavidin-coated paramagnetic particles, and mouse monoclonal anti-Tg antibody-alkaline phosphatase conjugate. The biotinylated antibodies and the sample Tg bind to the solid phase, while the conjugate antibody reacts with a different antigenic site on the Tg molecule. After incubation in a reaction vessel, materials bound to the solid phase are held in a magnetic field, while unbound materials are washed away. The chemiluminescent substrate Lumi-Phos530 is added to the vessel and light generated by the reaction is measured with a luminometer. Light production is directly proportional to the concentration of Tg in the sample. The amount of analyte in the sample is determined from a stored, multipoint calibration curve.(Instruction manual: Access Thyroglobulin Assay. Beckman Coulter, Inc, Fullerton, CA, 2010)


For all samples with Tg concentrations greater than 1.0 ng/mL, a dilution series is performed. A linear dilution excludes hooking and most major interferences. Samples that contain Tg less than or equal to 1.0 ng/mL are spiked with exogenous Tg to identify possible interferences that may cause a false-low result.

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


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; 6 a.m.-9 p.m.

Saturday; 6:30 a.m.-1 p.m.

Analytic Time Defines the amount of time it takes the laboratory to setup and perform the test. This is defined in number of days. The shortest interval of time expressed is "same day/1 day," which means the results may be available the same day that the sample is received in the testing laboratory. One day means results are available 1 day after the sample is received in the laboratory.

Same day/1 day

Maximum Laboratory Time Defines the maximum time from specimen receipt at Mayo Clinic Laboratories until the release of the test result

3 days

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

12 months

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