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HelpTest Code HTGR Thyroglobulin, Tumor Marker Reflex, Serum
Useful For
Reporting of accurate thyroglobulin results, depending on the antithyroglobulin antibodies status of the patient
Accurate measurement of serum thyroglobulin in patients with known or suspected antithyroglobulin autoantibodies or possible heterophile antibodies
Testing Algorithm
This test begins with the analysis of thyroglobulin antibody by immunoassay. If the thyroglobulin antibody result is negative (<1.8 IU/mL), then thyroglobulin testing will be performed by immunoassay.
If the thyroglobulin antibody result is positive (≥1.8 IU/mL), then thyroglobulin testing will be performed by mass spectrometry.
Reporting Name
Thyroglobulin Reflex to MS or IASpecimen Type
Serum RedSpecimen Required
Patient Preparation: For 12 hours before specimen collection, patient should not take multivitamins or dietary supplements (eg, hair, skin, and nail supplements) containing biotin (vitamin B7).
Collection Container/Tube: Red top (serum gel/SST are not acceptable)
Submission Container/Tube: Plastic vial
Specimen Volume: 2 mL
Collection Instructions: Centrifuge and aliquot serum into a plastic vial.
Specimen Minimum Volume
1.25 mL
Specimen Stability Information
| Specimen Type | Temperature | Time | Special Container |
|---|---|---|---|
| Serum Red | Refrigerated (preferred) | 7 days | |
| Frozen | 30 days | ||
| Ambient | 72 hours |
Reject Due To
| Gross hemolysis | Reject |
| Gross lipemia | OK |
| Gross icterus | Reject |
Reference Values
Thyroglobulin Antibody: <1.8 IU/mL
THYROGLOBULIN, TUMOR MARKER
Athyrotic: <0.1 ng/mL
Intact thyroid: ≤33 ng/mL
Method Description
The Access Thyroglobulin Antibody II assay (TgAb) is a sequential 2-step immunoenzymatic (sandwich) assay, performed on a Beckman Coulter Unicel DxI 800 system. A sample is added to a reaction vessel with paramagnetic particles coated with the thyroglobulin protein. The serum TgAb binds to the thyroglobulin. After incubation in a reaction vessel, materials bound to the solid phase are held in place by a magnetic field, while unbound materials are washed away. The thyroglobulin-alkaline phosphatase conjugate is added and binds to the TgAb. After the second incubation, materials bound to the solid phase are held in place by a magnetic field, while unbound materials are washed away. Then, the chemiluminescent substrate, Lumi-Phos 530 is added to the reaction vessel, and light generated by the reaction is measured with a luminometer. The light production is directly proportional to the concentration of thyroglobulin antibody in the sample.(Package insert: Access Thyroglobulin Antibody II. Beckman Coulter Inc; 07/2021)
Thyroglobulin by immunoassay is performed using a Beckman Coulter Unicel DxI 800 system. The Access Thyroglobulin (Tg) assay is a simultaneous 1-step immunoenzymatic (sandwich) assay. A sample is added to a reaction vessel, along with a biotinylated mixture of 4 monoclonal anti-Tg antibodies, streptavidin-coated paramagnetic particles, and monoclonal anti-Tg antibody alkaline phosphatase conjugate. The biotinylated antibodies and the serum 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. Then, the chemiluminescent substrate Lumi-Phos 530 is added to the vessel, and light generated by the reaction is measured with a luminometer. The light production is directly proportional to the concentration of Tg in the sample.(Package insert: Access Thyroglobulin. Beckman Coulter Inc.; 10/2023)
Thyroglobulin by mass spectrometry is performed as follows: serum is subjected to salt fractionation. The fractionated serum is then reduced, alkylated, and digested with trypsin. Tryptic fragments are further purified by immunocapture with antibodies specific to the individual fragments. Finally, these fragments are analyzed by liquid chromatography tandem mass spectrometry.(Unpublished Mayo method)
Day(s) Performed
Monday through Friday
Report Available
1 to 6 daysPerforming Laboratory
Mayo Clinic Laboratories in Rochester
Test Classification
This test has been cleared, approved, or is exempt by the US Food and Drug Administration and is used per manufacturer's instructions. Performance characteristics were verified by Mayo Clinic in a manner consistent with CLIA requirements.CPT Code Information
86800
84432 (if appropriate)
LOINC Code Information
| Test ID | Test Order Name | Order LOINC Value |
|---|---|---|
| HTGR | Thyroglobulin Reflex to MS or IA | 56536-6 |
| Result ID | Test Result Name | Result LOINC Value |
|---|---|---|
| TGABR | Thyroglobulin Antibody, S | 56536-6 |
Reflex Tests
| Test ID | Reporting Name | Available Separately | Always Performed |
|---|---|---|---|
| HTGT | Thyroglobulin, Tumor Marker, IA, S | No | No |
| TGMS | Thyroglobulin, Mass Spec., S | Yes | No |
Method Name
Immunoenzymatic Assay
Forms
If not ordering electronically, complete, print, and send an Oncology Test Request (T729) with the specimen.