Quick Facts
- Sample: Blood (serum)
- Fasting: Not required
- Turn-around: 5-7 business days. May take longer based on weather, holiday, or lab delays.
Benefits
- Monitor thyroid cancer recurrence after surgery or radioactive iodine treatment
- Detect autoimmune thyroid conditions like Hashimoto's thyroiditis early
- Get accurate results with specialized testing methods based on antibody status
- Skip doctor visits with convenient direct-access testing
- Receive results within days for timely health decisions
- Track treatment progress with reliable tumor marker monitoring
Who Is This Test For?
- Thyroid cancer survivors monitoring for recurrence after treatment
- People with thyroid symptoms like fatigue, weight changes, or neck swelling
- Those with family history of thyroid cancer or autoimmune diseases
- Patients with abnormal TSH needing further thyroid evaluation
- Individuals taking thyroid medications requiring treatment monitoring
How It Works – Just 3 Steps
- Order online – Just order your test online and schedule an appointment at your convenience
- Visit lab – Quick blood draw at any participating location
- Get results – Results delivered securely within days
FAQ
What does this test measure? Thyroglobulin protein levels and antibodies that may interfere with accurate measurement.
Is this test painful? Just a standard blood draw with minimal discomfort lasting seconds.
Can I eat before the test? Yes, no fasting required for this blood test.
What if my antibodies are positive? Your sample will be tested using RIA method for more accurate thyroglobulin measurement.
How accurate are the results? Highly accurate when proper testing method is used based on antibody status (LabCorp 2025).
Should I stop thyroid medication? Consult your doctor; some medications may affect results but shouldn't be stopped without guidance.
More Details
What is the purpose of this test?
This test measures thyroglobulin protein, which serves as a tumor marker for thyroid cancer monitoring, and detects thyroglobulin antibodies that indicate autoimmune thyroid disease. Thyroglobulin is produced by thyroid tissue, so elevated levels after thyroid removal may signal cancer recurrence (ThyCa 2025). The antibody component identifies immune system attacks on thyroid tissue and potential interference with thyroglobulin measurement accuracy.
Who would benefit from this test?
Thyroid cancer patients benefit most from regular monitoring after surgery or radioactive iodine therapy. People with suspected autoimmune thyroid conditions like Hashimoto's thyroiditis or Graves' disease can confirm diagnosis. Those experiencing thyroid symptoms or having abnormal TSH results may need this comprehensive evaluation. Individuals with family history of thyroid disorders can screen for early disease detection (Mayo Clinic 2024).
When should I order this test?
Order after thyroid cancer treatment to establish baseline levels and monitor recurrence. Test when experiencing thyroid symptoms like unexplained weight changes, fatigue, or neck swelling. Consider testing if other thyroid function tests show abnormalities or if autoimmune thyroid disease is suspected. Best performed at least 6 weeks after thyroid surgery or radioiodine therapy for accurate baseline measurement (Medical News Today 2025).
How do I interpret the results?
Undetectable Tg, Negative TgAb
- What it means: Normal after complete thyroid removal
- Typical action: Continue regular monitoring
Rising Tg, Negative TgAb
- What it means: Possible cancer recurrence
- Typical action: Imaging studies and specialist consultation
Any Tg level, Positive TgAb
- What it means: Autoimmune thyroid disease present
- Typical action: RIA (radioimmunoassay) testing for accurate Tg measurement
High TgAb levels
- What it means: Active autoimmune process
- Typical action: Monitor disease progression and treatment response
Approximately 15-20% of thyroid cancer patients have interfering antibodies requiring specialized RIA testing for accurate results.
Disclaimer: Reference ranges may vary by laboratory. Listed ranges are general guidelines and may differ from those used by the performing lab. Always consult your healthcare provider for interpretation.
Pre-test preparation
No fasting required before this blood test. Inform the laboratory about current thyroid medications, as some may affect results. Avoid scheduling immediately after thyroid procedures; wait at least 6 weeks post-surgery or radioiodine therapy. Continue taking prescribed medications unless specifically instructed otherwise by your healthcare provider. Stay hydrated and wear comfortable clothing with easy arm access for blood draw.
How often should I get tested?
- Post-thyroid cancer treatment: Every 6–12 months for surveillance
- Autoimmune thyroid disease: Every 6–12 months to monitor progression
- Normal results, no symptoms: As recommended by healthcare provider
- Abnormal or rising levels: Every 3–6 months until stable
Why early detection matters
Early detection of thyroid cancer recurrence through thyroglobulin monitoring significantly improves treatment outcomes and survival rates. Catching autoimmune thyroid disease early prevents progression to more severe complications like heart problems or severe hypothyroidism. Regular monitoring enables timely treatment adjustments and reduces long-term healthcare costs. Studies show that consistent surveillance leads to better quality of life and more successful treatment outcomes (PubMed 2022).
Related tests you may consider
TSH Test – Evaluates overall thyroid gland function and hormone regulation
Anti-TPO Antibody Test – Confirms autoimmune thyroiditis diagnosis alongside TgAb testing
Free T3 and T4 Blood Test Panel – Measures active thyroid hormones for comprehensive evaluation
