Thyroglobulin, Serum with Reflex to IA or LC-MS/MS
Test Mnemonic
THYRORF
CPT Codes
- 84432 - QTY (1)
- 86800 - QTY (1)
Performing Laboratory
Cleveland Clinic Laboratories
Specimen Requirements
| Volume | Type | Container | Collect Temperature | Transport Temperature | Special Instructions |
|---|---|---|---|---|---|
| 2.5 mL | Serum | SST (Gold) | Centrifuge and refrigerate. |
Alternate Specimen Requirements
| Volume | Type | Container | Collect Temperature | Transport Temperature | Special Instructions |
|---|---|---|---|---|---|
| 2.5 mL | Serum | No additive (Red) | Centrifuge, aliquot and refrigerate. |
Minimum Specimen Requirements
| Volume | Type | Container | Collect Temperature | Transport Temperature | Special Instructions |
|---|---|---|---|---|---|
| 1.2 mL |
Stability
| Environmental Condition | Description |
|---|---|
| Ambient | 8 hours |
| Refrigerated | 7 days |
| Frozen | 30 days |
Days Performed
Mon - Fri
Turnaround Time
1 - 3 days
Methodology
| Name | Description |
|---|---|
| Chemiluminescence Immunoassay (CLIA) | |
| Liquid Chromatography-Tandem Mass Spectrometry (LC-MS/MS) |
Special Info
In this test, Thyroglobulin Antibody is analyzed by the Access Thyroglobulin Antibody assay (Beckman). If the result is negative (<4.0 IU/mL), the Thyroglobulin tests will be performed by immunoassay using the Access Thyroglobulin assay (Beckman). If the antibody result is positive (>=4.0 IU/mL), the Thyroglobulin tests will be performed by LC-MS/MS. Results obtained from different assay method or kits cannot be used interchangeably.
Clinical Info
Serum thyroglobulin levels correlate well with the volume of differentiated thyroid tissue, hence are increased in thyrotoxicosis, thyroiditis, iodine deficiency, benign thyroid adenomas, and thyroid cancer. Thus although it is unsuitable as a screening tool for differentiated thyroid cancer (DTC), it is a highly sensitive marker for the detection of residual or recurrent disease after a total thyroidectomy and successful radioiodine remnant ablation. Presence of thyroglobulin autoantibodies interfere in the assay and thyroglobulin levels are underestimated in the antibody positive patients. In the presence of anti-thyroglobulin antibodies, thyroglobulin measurement by LC-MS/MS provides accurate thyroglobulin results. The thyroglobulin test is intended for surveillance of patients with differentiated thyroid cancer who have had a thyroidectomy with or without radioactive ablation. The presence of thyroglobulin antibodies may interfere with thyroglobulin measurement by immunoassay and cause falsely-low results.
Reflex Tests
The following additional test(s) may be ordered depending on results: