Tumor Marker and Monitoring Tool for Thyroid Disorders.
Thyroglobulin (TG) is a protein produced exclusively by the thyroid gland. This test measures the amount of thyroglobulin in the blood and is primarily used as a tumor marker for patients with a history of thyroid cancer. It is also helpful in evaluating thyroid inflammation (thyroiditis) and in monitoring thyroid function after treatment like surgery or radioactive iodine therapy. It is not used for initial diagnosis of thyroid conditions but rather for post-treatment surveillance in known cases.
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How our test process works!
Overview
Purpose:
Measures the concentration of thyroglobulin, a glycoprotein produced only by thyroid follicular cells.
Used primarily for:
- Monitoring differentiated thyroid cancer (especially papillary and follicular types) after thyroidectomy or radioactive iodine therapy.
- Detecting residual, recurrent, or metastatic thyroid cancer.
- Occasionally used in evaluation of thyroid function or thyroiditis, but not a first-line test.
Risk Assessment
- Follow-up after thyroid cancer surgery or ablation
- Surveillance for recurrence or metastasis in thyroid cancer
- Evaluation of:
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Thyroiditis (e.g., Hashimoto's, subacute)
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Thyrotoxicosis
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Factitious thyrotoxicosis (to differentiate from thyroiditis)
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Normal Range
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Typical Range (adults):
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1.6 – 59 ng/mL (varies slightly by lab)
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After thyroidectomy for cancer:
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Target: <0.2 ng/mL (with TSH suppression), or <1 ng/mL after TSH stimulation
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Note: Always consider lab-specific reference ranges and presence of Tg antibodies.
Interpretation of Results
| Tg Level | Clinical Implication |
| Undetectable/Low | Expected after total thyroidectomy or successful radioactive ablation. |
| Elevated | May indicate residual thyroid tissue, recurrent or metastatic thyroid cancer |
| Fluctuating or rising | Suggests recurrence or progression in patients under surveillance |
| High in thyroiditis | Tg can be transiently elevated due to follicular cell destruction |
Important: Interpretation requires simultaneous anti-thyroglobulin antibody (TgAb) testing, as TgAb can falsely lower or interfere with Tg levels.
Sample Type
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Specimen: Serum
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Collection:
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Plain (red-top) or serum separator tube (SST)
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Fasting not required
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Timing:
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Baseline after surgery, then periodic surveillance
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May also be tested after TSH stimulation (either by thyroxine withdrawal or recombinant TSH).
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Frequently Asked Question
THYROGLOBULIN (TG) test
Tumor Marker and Monitoring Tool for Thyroid Disorders.
Thyroglobulin (TG) is a protein produced exclusively by the thyroid gland. This test measures the amount of thyroglobulin in the blood and is primarily used as a tumor marker for patients with a history of thyroid cancer. It is also helpful in evaluating thyroid inflammation (thyroiditis) and in monitoring thyroid function after treatment like surgery or radioactive iodine therapy. It is not used for initial diagnosis of thyroid conditions but rather for post-treatment surveillance in known cases.
Covid Safety
Assured
Free Report
Counselling
