Order Code IETG Interference Evaluation Heterophile, Thyroglobulin Tumor Marker, Serum

Ordering Guidance

If interference or heterophile testing is not required, order HTG2 / Thyroglobulin, Tumor Marker, Serum.

For fine-needle aspirate specimens, order TFNAB / Thyroglobulin, Tumor Marker, Fine-Needle Aspiration Biopsy Needle Wash.

Specimen Required

Patient Preparation: For 12 hours before specimen collection do not take multivitamins or dietary supplements containing biotin (vitamin B7), which is commonly found in hair, skin, and nail supplements and multivitamins.

Collection Container/Tube: Red top (serum gel/SST are not acceptable)

Submission Container/Tube: Plastic vial

Specimen Volume: 2.5 mL

Collection Instructions: Centrifuge and aliquot serum into a plastic vial.

Useful For

Evaluation of suspected interference from heterophile antibodies causing a falsely elevated thyroglobulin result

Profile Information

Test ID	Reporting Name	Available Separately	Always Performed
TGII	TG, Interference Interpretation	No	Yes
TGQN	Thyroglobulin, Tumor Marker, S	Yes, (Order HTG2)	Yes
TGABI	Thyroglobulin Antibody, S	Yes, (Order HTG2)	Yes
TGMS	Thyroglobulin, Mass Spec., S	Yes	Yes

Testing Algorithm

Heterophile antibody evaluation consists of comparison of thyroglobulin (Tg) concentrations obtained by immunoassay with the following:

-Tg concentrations following pretreatment with commercial heterophile blocking reagents

-Tg concentrations obtained by mass spectrometry

-Tg concentrations obtained by serial dilutions of the sample

In all samples the presence of anti-thyroglobulin antibodies are evaluated.

Method Name

TGQN/TGABI: Immunoenzymatic Assay

TGMS: Tryptic Protein Fragmentation, purified with Immunocapture, Analysis by Liquid Chromatography-Tandem Mass Spectrometry (LC-MS/MS)

(This service is performed pursuant to an agreement with SISCAPA Assay Technologies Inc. covering US Patent 7,632,686)

TGII: Medical Interpretation

Reporting Name

Interference Eval, Heterophile, TG

Specimen Type

Serum Red

Specimen Minimum Volume

2 mL

Specimen Stability Information

Specimen Type	Temperature	Time
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 TUMOR MARKER

Athyrotic: <0.1 ng/Ml

Intact thyroid: ≤33 ng/mL

THYROGLOBULIN, MASS SPECTROMETRY

Athyrotic: <0.2 ng/mL

Healthy individuals with intact, functioning thyroid: ≤33 ng/mL

THYROGLOBULIN ANTIBODY

<1.8 IU/mL

Reference values apply to all ages.

Method Description

The specimen will be evaluated for potential heterophile antibody interference in the Beckman Coulter Access Thyroglobulin Immunoassay. Heterophile antibody evaluation will consist of measurement of thyroglobulin antibody, pretreatment with commercial heterophile antibody blocking reagents, testing on an alternate platform liquid chromatography-tandem mass spectrometry (LC-MS/MS), and serial dilution of the sample.

Heterophile blocking agents consisted of HBT (Heterophile Blocking Tube) - Scantibodies Incorporated for the Beckman Assay. This blocker contains murine (HBT) derived proteins in a buffered salt solution.

Thyroglobulin, Tumor Marker:

The Beckman Coulter UniCel DxI 800 is the instrument used for thyroglobulin tumor marker testing. The Access Thyroglobulin (2) assay is a simultaneous one-step immunoenzymatic ("sandwich") assay. the sample is added to a reaction vessel, along with a biotinylated mixture of four monoclonal anti- thyroglobulin (Tg) antibodies (TgAb), streptavidin-coated paramagnetic particles, and monoclonal anti-Tg antibody alkaline phosphatase conjugate. The biotinylated antibodies and the serum thyroglobulin bind to the solid phase, while the conjugate antibody reacts with a different antigenic site on the thyroglobulin 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 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 thyroglobulin in the sample. The amount of analyte in the sample is determined from a stored, multi-point calibration curve.(Package insert: Access Thyroglobulin. Beckman Coulter Inc.; 06/2021)

Thyroglobulin Antibody:

The Access Thyroglobulin Antibody II assay is a sequential 2-step immunoenzymatic ("sandwich") assay. The sample is added to a reaction vessel with paramagnetic particles coated with Tg 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 Tg-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 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 TgAb in the sample. The amount of analyte in the sample is calculated by means of a stored, multi-point calibration curve.(Package insert: Thyroglobulin Antibody II Instructions for Use. Beckman Coulter Inc; 2019)

Thyroglobulin, Alternative Method:

Serum is fractionated by a salting out method. 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 LC-MS/MS.(Unpublished Mayo method)

Thyroglobulin, Interference Interpretation:

A laboratory director will review the results and provide an interpretation.

Day(s) Performed

Monday through Saturday

Performing Laboratory

Mayo Clinic Laboratories in Rochester

CPT Code Information

84432

86800