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HelpTest Code TGQN Thyroglobulin, Tumor Marker, Serum
Specimen Required
Only orderable as part of profile. For more information see IETG / Interference Evaluation Heterophile, Thyroglobulin Tumor Marker, Serum.
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
Quantitative thyroglobulin measurement as a part of evaluating suspected interference from heterophile antibodies causing a falsely elevated thyroglobulin result
Method Name
Only orderable as part of profile. For more information see IETG / Interference Evaluation Heterophile, Thyroglobulin Tumor Marker, Serum.
Immunoenzymatic Assay
Reporting Name
Thyroglobulin, Tumor Marker, SSpecimen Type
Serum RedSpecimen Minimum Volume
2 mL
Specimen Stability Information
| Specimen Type | Temperature | Time | Special Container |
|---|---|---|---|
| Serum Red | Refrigerated (preferred) | 14 days | |
| Frozen | 90 days | ||
| Ambient | 7 days |
Reference Values
Only orderable as part of profile. For more information see IETG / Interference Evaluation Heterophile, Thyroglobulin Tumor Marker, Serum.
Athyrotic: <0.1 ng/mL
Intact thyroid: ≤33 ng/mL
Interpretation
Specimens are evaluated for the presence of potential interfering anti-thyroglobulin (TgAb) and heterophile antibody interference in the Beckman Access thyroglobulin (Tg) immunoassay. While the presence of TgAb can result in falsely low Tg concentrations in the Beckman immunoassay, the presence of heterophile antibodies can result in falsely elevated Tg concentrations in the Beckman immunoassay. Following investigation of the presence of TgAb, heterophile antibody evaluation consists of pretreatment with commercial heterophile antibody blocking reagents, serial dilutions of the sample and testing on an alternate platform generally unaffected by the presence of heterophile antibodies or TgAb (ie, Tg liquid chromatography-tandem mass spectrometry [Tg-MS]). The presence of heterophile antibody interference in the Beckman Access Tg immunoassay is not suspected when the results from the pretreatment, serial dilutions and the alternative platform (Tg-MS) agree with the original result.
The presence of heterophile antibody interference in the Beckman Access Tg immunoassay is suspected when 1 or more of the following are observed: a significant decrease in Tg concentration (>20%) upon treatment of the sample with heterophile antibody blocking reagents, lack of linearity upon serial dilutions, or a significant difference in Tg concentration on the alternate platform (Tg-MS). When a heterophile antibody interference affecting the Beckman Access immunoassay is suspected, the Tg result from this assay is considered false-positive and should not be used in clinical management.
Clinical Reference
1. Barbesino G, Algeciras-Schimnich A, Bornhorst JA: False positives in thyroglobulin determinations due to the presence of heterophile antibodies: an underrecognized and consequential clinical problem. Endocr Pract. 2021 May;27(5):396-400. doi: 10.1016/j.eprac.2020.10.011
2. American Thyroid Association (ATA) Guidelines Taskforce on Thyroid Nodules and Differentiated Thyroid Cancer, Cooper DS, Doherty GM, et al: Revised American Thyroid Association management guidelines for patients with thyroid nodules and differentiated thyroid cancer. Thyroid. 2009 Nov;19(11):1167-1214
3. Netzel BC, Grebe SKG, Algeciras-Schimnich A: Usefulness of a thyroglobulin liquid chromatography-tandem mass spectrometry assay for evaluation of suspected heterophile interference. Clin Chem. 2014 Jul;60(7):1016-1018
4. Algeciras-Schimnich A: Thyroglobulin measurement in the management of patients with differentiated thyroid cancer. Crit Rev Clin Lab Sci. 2018 May;55(3):205-218
5. Ward G, Simpson A, Boscato L, Hickman PE: The investigation of interferences in immunoassay. Clin Biochem. 2017 Dec;50(18):1306-1311
Day(s) Performed
Monday through Friday
Report Available
3 to 5 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
84432
LOINC Code Information
| Test ID | Test Order Name | Order LOINC Value |
|---|---|---|
| TGQN | Thyroglobulin, Tumor Marker, S | 96460-1 |
| Result ID | Test Result Name | Result LOINC Value |
|---|---|---|
| TGQN | Thyroglobulin, Tumor Marker, S | 96460-1 |