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
THYCA
MiChart Code
Thyroid Cancer Monitoring (Sendout)
Laboratory
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.
Container
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.
