Thyroglobulin Tg Test
Short Name: Tg Test
Also known as: Thyroglobulin test, Tg assay, Thyroglobulin tumor marker
Thyroglobulin Tg Test test available at DNA Labs India for ₹1,989. Uses Chemiluminescent Immunoassay on Serum samples. Results in Reports are usually available the same day or within 24 hours after the sample is received. Reports can be downloaded from the online portal or received by email and WhatsApp.. Free home collection in 300+ cities across India.
🩺 Medically Reviewed By
Dr Pasupathy Arumugam
Consultant Pathologist · Reg: 21521
Last reviewed: September 7, 2026
Overview
The purpose of the Thyroglobulin Tg Test is to monitor patients with differentiated thyroid cancer after thyroidectomy or radioactive iodine ablation, to detect persistent or recurrent disease, and to determine whether any functional thyroid tissue remains. It is also used as an aid in detecting thyroid cancer metastasis to lymph nodes and in assessing response to treatment.
- Test Code
- 3694
- ICD Code
- C73
- Price
- ₹1,989
- Sample Type
- Serum
- Result Time
- Reports are usually available the same day or within 24 hours after the sample is received. Reports can be downloaded from the online portal or received by email and WhatsApp.
- Fasting Required
- No
- Method
- Chemiluminescent Immunoassay
Sample Collection
At least 6 weeks should elapse after thyroidectomy, needle biopsy, or Iodine-131 therapy before specimen collection. Inform your doctor about any biotin supplements, prior imaging, or recent procedures.
Method: Venipuncture
Laboratory Analysis
A blood sample is collected from a vein in your arm. The procedure is quick and routine. You may feel a brief pinch or sting at the needle site.
Report Delivery
No special precautions are needed after sample collection. You can resume normal activities immediately. The sample should be transported refrigerated or frozen as advised by the laboratory.
Timeline: Reports are usually available the same day or within 24 hours after the sample is received. Reports can be downloaded from the online portal or received by email and WhatsApp.
Patient Instructions
About This Test
Who Should Get This Test
The purpose of the Thyroglobulin Tg Test is to monitor patients with differentiated thyroid cancer after thyroidectomy or radioactive iodine ablation, to detect persistent or recurrent disease, and to determine whether any functional thyroid tissue remains. It is also used as an aid in detecting thyroid cancer metastasis to lymph nodes and in assessing response to treatment.
How to Prepare
- At least 6 weeks should elapse after thyroidectomy, needle biopsy, or Iodine-131 therapy before specimen collection
- Collect 2 mL (1 mL minimum) serum from one SST
- Ship sample refrigerated or frozen
- Do not rely on room temperature storage
Doctor's Notes
Reviewed by Dr Pasupathy Arumugam — MBBS, MD (Pathology) · Reg. No. 21521
"Serial Tg measurements are the cornerstone of surveillance for differentiated thyroid cancer. A single value is less informative than the trend over time, and results should always be interpreted together with TSH and Tg antibody levels."
Last medically reviewed: September 7, 2026
Test Parameters & Specifications
Sample Stability
- Specimen collected less than 6 weeks after thyroidectomy, needle biopsy, or Iodine-131 therapy
- Sample not stored or transported under appropriate temperature
- Hemolysed, lipemic, or icteric sample
- Insufficient sample volume
Understanding Your Results
Suggests no significant residual thyroid tissue or recurrent cancer; this is the desired response.
Suspicious for persistent or recurrent differentiated thyroid cancer; further imaging or evaluation is indicated.
May be due to benign thyroid conditions such as goitre, thyroiditis, Graves disease, or other benign thyroid disease; not diagnostic of cancer alone.
Indicates good response to therapy and low likelihood of recurrence; continued periodic surveillance is still required.
Consult your oncologist or treating physician if your Tg level is rising, if you develop a new neck lump, pain, hoarseness, difficulty swallowing, or any new symptom, and if you are unsure how to interpret your Tg report.
Limitations
- ⚠Tg measurement is not reliable in patients with anti-thyroglobulin antibodies unless a mass spectrometry method is used
- ⚠A single Tg value cannot differentiate between benign residual tissue and cancer when thyroid remnant is significant
- ⚠Not indicated for medullary or anaplastic thyroid cancer
- ⚠Reference ranges are method- and laboratory-specific
- ⚠The test is not useful for screening thyroid cancer in the general population
Risks & Considerations
- ●Mild pain or discomfort at the puncture site
- ●Bruising or mild bleeding
- ●Dizziness or feeling lightheaded
- ●Rare risk of infection or prolonged bleeding
Interfering Factors
- ●Anti-thyroglobulin antibodies (TgAb) can interfere with Tg immunoassays and cause falsely low or falsely high results
- ●Biotin supplements may interfere with chemiluminescent immunoassay results
- ●Heterophilic antibodies or human anti-mouse antibodies may cause assay interference
- ●Recent thyroidectomy, thyroid needle biopsy, or Iodine-131 therapy may cause temporary changes
- ●Extremely lipemic, hemolysed, or improperly stored samples may affect accuracy
Compare With Similar Tests
| Test | Thyroglobulin Tg Test | Thyroid Stimulating Hormone (TSH) Test | Anti-Thyroglobulin Antibody (TgAb) Test | Thyroid Ultrasound |
|---|---|---|---|---|
| Comparison | Thyroglobulin Tg Test |
Frequently Asked Questions
What is the Thyroglobulin Tg Test?
How much does the Thyroglobulin Tg Test cost at DNA Labs India?
Why is the Tg test used in thyroid cancer?
Is fasting required for the Thyroglobulin Tg Test?
What sample type is needed for this test?
How long does it take to get the Tg test report?
What does a high Tg level mean after thyroidectomy?
Can thyroid antibodies affect the Tg test?
How often should I get the Thyroglobulin Tg Test done?
Is home sample collection available for the Tg test?
Does insurance cover the Thyroglobulin Tg Test?
What conditions other than cancer can raise thyroglobulin?
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