Test Overview

Test Methodology


Test Usage

Measurement of thyroglobulin (Tg) is useful in the detection of residual or recurrent thyroid cancer. Many individuals develop auto-antibodies to Tg (Tg Ab) and the presence of Tg Ab interferes with the measurement of immunoassay Tg. It is therefore necessary to identify the presence/absence of Tg Ab before measuring Tg. The panel will first measure Tg Ab; if the patient is Tg Ab negative, Tg will be measured using a Second Generation immunoassay with increased low-level sensitivity to 0.05 ng/mL. If the Tg Ab is positive, Tg will be measured by tandem mass spectroscopy. The LC/MS/MS assay will provide quantitative measurement of Tg in the presence of Tg Ab.

Reference Range*

< or = 1 IU/mL

* Reference ranges may change over time. Please refer to the original patient report when evaluating results.

Test Details

Days Test Performed

Monday - Friday

Analytic Time

8-10 days

Soft Order Code


MiChart Code

Thyroid Cancer Monitoring (Sendout)



Laboratory Reference

Quest Valencia 90814

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Specimen Requirements

Rejection Criteria

Hemolyzed, icteric, or lipemic specimens are not acceptable. Plasma is not acceptable.


Red Top Tube
Yellow Top Tube

Normal Volume

2.5 mL serum

Minimum Volume

1.5 mL serum

Additional Information

Test includes Thyroglobulin Antibody. If Thyroglobulin Ab result is < or = 1 IU/mL, then Thyroglobulin, Second Generation (Beckman Coulter) will be performed at an additional charge (CPT 84432). If Thyroglobulin Ab result is >1 IU/mL, then Thyroglobulin, LC/MS/MS will be performed at an additional charge (CPT 84432). By ordering this test the clinician acknowledges that additional reflex testing will be performed and billed at a separate additional charge if indicated. Test sent to Quest Diagnostics Nichols Institute of Valencia.

Billing Information

Fee Codes

CPT Code


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