Thyroid Cancer (Thyroglobulin) Monitoring

Test Code

CPT Codes

If Thyroglobulin Antibody is negative, then Thyroglobulin is tested on the Beckman Coulter DxI (CPT code: 84432).
If Thyroglobulin Antibody is positive, then Thyroglobulin is tested by LC/MS/MS (CPT code: 84432).

Preferred Specimen
3 mL serum

Minimum Volume
1.5 mL

Dietary supplements containing biotin may interfere in assays and may skew results to be either falsely high or falsely low. For patients receiving the recommended daily doses of biotin, draw samples at least 8 hours following the last biotin supplementation. For patients on mega-doses of biotin supplements, draw samples at least 72 hours following the last biotin supplementation.

Transport Container
Plastic screw-cap vial

Transport Temperature
Room temperature

Specimen Stability
Room temperature: 6 days
Refrigerated: 7 days
Frozen: 28 days

Reject Criteria (Eg, hemolysis? Lipemia? Thaw/Other?)
Hemolysis • Lipemia • Plasma • Icteric


Setup Schedule
Set up: Sun, Tues-Sat; Report available: 7-8 days

Reference Range
Thyroglobulin Antibody ≤1 IU/mL
  Thyroglobulin Athyrotic: <0.1 ng/mL
  Thyroglobulin, LC/MS/MS Athyrotic: <0.4 ng/mL

Clinical Significance
Thyroglobulin measurements are most useful in the postoperative monitoring of patients with papillary, follicular, and Hurthle cell carcinomas. However, approximately 20% of individuals develop autoantibodies to thyroglobulin. Since these antibodies interfere with immunoassay measurement of thyroglobulin, it is necessary to determine the presence or absence of antibodies before measuring thyroglobulin. This panel provides a sensitive method for determination of thyroglobulin autoantibodies, with subsequent measurement of thyroglobulin by either a sensitive immunoassay (Tg Ab negative samples) or LCMSMS (Tg Ab positive samples). The mass spectrometry assay has no interference from autoantibodies.

Performing Laboratory
Quest Diagnostics Nichols Institute
14225 Newbrook Drive
Chantilly, VA 20153

The CPT Codes provided in this document are based on AMA guidelines and are for informational purposes only. CPT coding is the sole responsibility of the billing party. Please direct any questions regarding coding to the payor being billed. Any Profile/panel component may be ordered separately. Reflex tests are performed at an additional charge.