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Test Code LAB3241 Thyroglobulin, Tumor Marker Reflex, Serum

Additional Codes

SQ: HTGRM

MAYO: HTGR

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 IA

Specimen Type

Serum Red


Specimen 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 days

Performing 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.

Secondary ID

62936