The short answer
Thyroglobulin antibodies show your immune system targeting a protein your thyroid uses to make hormone. They matter most after thyroid cancer, where they can hide the cancer marker doctors rely on.5 Labcorp’s newest reports give a range of 0.0 to 1.4 IU/mL.2
- A good result
- Within Labcorp’s range, 0.0 to 1.4 IU/mL on its newest reports.2
Check your result
Type the number from your report. It stays on this page.
- Within range Under 1.5
- Low level 1.5 to 4.0
- Positive 4.1 or more
- Within range Under 1.5
- Detected after cancer 1.5 or more
Enter your result to see what it means and what to do next.
Got a result from another lab? Ask Picardo about it. The app explains your results, and a physician can follow up.
The 1.5 line is just above Labcorp’s newest range.2 The 4 line is the level the test’s maker found in some people without thyroid disease.2 The bar isn’t to scale.
Within Labcorp’s range
No sign of thyroglobulin antibodies above Labcorp’s range.2
Nothing to worry about.
- 1 If you haven’t had TPO antibodies tested, they’re the more useful test for thyroid autoimmunity.3,4
Low level: often not meaningful on its own
Labcorp flags any level above its range, partly because any antibody can throw off a thyroglobulin test.1 For autoimmunity, low levels mean less. The test’s maker found that about 4% of people without thyroid disease have levels up to 4 IU/mL.2 TPO antibodies and TSH tell you more.3,4
Not a worry on its own.
- 1 Check TPO antibodies and TSH if you haven’t.3,4
- 2 If you’re pregnant or planning to be, it’s managed like a positive TPO result, with regular TSH checks.4
Positive: a sign of thyroid autoimmunity
Thyroglobulin antibodies point to autoimmune thyroid disease, as in Hashimoto’s. In a large US survey, though, they weren’t linked to an underactive thyroid the way TPO antibodies were.3 In pregnancy, women with only thyroglobulin antibodies had more subclinical hypothyroidism than women with neither antibody, 8.1% against 2.2%.7
Not a worry now, but worth knowing for the future.
- 1 Check TSH and TPO antibodies if you haven’t.3,4
- 2 If you’re pregnant or planning to be, it’s managed like a positive TPO result, with regular TSH checks before and during pregnancy.4
Within range after thyroid cancer
No antibodies above Labcorp’s range, so your thyroglobulin result is much less likely to be thrown off by them.2,5
Nothing to worry about.
Detected after thyroid cancer: follow the trend
About 1 in 5 people treated for thyroid cancer have thyroglobulin antibodies.5 They can make thyroglobulin, the usual cancer marker, read falsely low, so imaging, usually neck ultrasound, leads follow-up, with the antibody trend as a guide.5 Falling levels are usually reassuring.1 Rising or newly appearing antibodies are a reason for a closer look, though new antibodies on their own don’t always mean the cancer is back.1,5
Not urgent on its own. The direction over time matters more than one number.
- 1 Have it done together with thyroglobulin, at the same lab and with the same method each time, so results can be compared.5
- 2 Expect ultrasound or other imaging to lead your follow-up while antibodies are present.5
- 3 If your level is rising, or antibodies have newly appeared, discuss it with your thyroid cancer team.5
What is a normal thyroglobulin antibodies level?
Labcorp’s newest sample report, from August 2026, gives a range of 0.0 to 1.4 IU/mL; older reports used 0.0 to 0.9.2,9 If your report uses the older range, go by its flag. Labcorp flags any level above its range, but a low level isn’t always meaningful.1 What a result means depends on why you’re testing:
Within Labcorp’s range
No sign of thyroglobulin antibodies above Labcorp’s range.2
Nothing to worry about.
Low level: often not meaningful on its own
Labcorp flags any level above its range, partly because any antibody can throw off a thyroglobulin test.1 For autoimmunity, low levels mean less. The test’s maker found that about 4% of people without thyroid disease have levels up to 4 IU/mL.2 TPO antibodies and TSH tell you more.3,4
Not a worry on its own.
Positive: a sign of thyroid autoimmunity
Thyroglobulin antibodies point to autoimmune thyroid disease, as in Hashimoto’s. In a large US survey, though, they weren’t linked to an underactive thyroid the way TPO antibodies were.3 In pregnancy, women with only thyroglobulin antibodies had more subclinical hypothyroidism than women with neither antibody, 8.1% against 2.2%.7
Not a worry now, but worth knowing for the future.
Detected after thyroid cancer: follow the trend
About 1 in 5 people treated for thyroid cancer have thyroglobulin antibodies.5 They can make thyroglobulin, the usual cancer marker, read falsely low, so imaging, usually neck ultrasound, leads follow-up, with the antibody trend as a guide.5 Falling levels are usually reassuring.1 Rising or newly appearing antibodies are a reason for a closer look, though new antibodies on their own don’t always mean the cancer is back.1,5
Not urgent on its own. The direction over time matters more than one number.
- 1 Have it done together with thyroglobulin, at the same lab and with the same method each time, so results can be compared.5
- 2 Expect ultrasound or other imaging to lead your follow-up while antibodies are present.5
- 3 If your level is rising, or antibodies have newly appeared, discuss it with your thyroid cancer team.5
What are thyroglobulin antibodies?
Thyroglobulin is the protein your thyroid uses to build its hormones. Thyroglobulin antibodies are your immune system targeting it. They matter in two very different situations: as a sign of thyroid autoimmunity, and as a source of error in a cancer test.
In a large US survey, about 1 in 10 people had thyroglobulin antibodies, more often women and older people. On their own, they weren’t linked to an underactive thyroid the way TPO antibodies were.1,3
When is a thyroglobulin antibody test useful?
After thyroid cancer, it’s essential. Guidelines call for measuring thyroglobulin antibodies with every thyroglobulin test, because the antibodies can make the cancer marker read falsely low.1,5
For thyroid autoimmunity, it’s a second-line test. TPO antibodies are more closely tied to an underactive thyroid, so they come first.3,4 The 2026 ATA pregnancy guideline sees no need to check thyroglobulin antibodies routinely around pregnancy.4 Some people do have only thyroglobulin antibodies, though, and in pregnancy that still goes with a higher chance of an underactive thyroid.7
Thyroglobulin antibodies after thyroid cancer
| After thyroid cancer, antibodies are | What it suggests |
|---|---|
| Not found | Thyroglobulin results are much less likely to be thrown off |
| Falling | Usually reassuring |
| Stable | Uncertain, so imaging guides follow-up |
| Rising, or newly found | A reason for a closer look, usually with imaging |
While antibodies are present, the 2025 ATA guideline makes imaging, such as neck ultrasound, the main way to watch for the cancer coming back, with the antibody trend as a guide.5 Use the same lab and test method each time, because results from different tests don’t match.5
Who should get a thyroglobulin antibody test?
- You’ve had surgery for thyroid cancer and are having thyroglobulin tests.5
- You’re pregnant or planning to be, your TPO antibodies are negative, your TSH is normal but near the top of the range, and you have a high chance of thyroid autoimmunity, such as another autoimmune disease or a close relative with one.4
For most people checking for thyroid autoimmunity, TPO antibodies are enough.3,4
How to get a thyroglobulin antibodies test, and what it costs
A thyroglobulin antibodies test costs $6.25 through Picardo.
Thyroglobulin antibodies test
- Results in 2 to 3 days, in the app
- Physician follow-up if you want one
- Free Labcorp draw, or $75 at home
- No other fees. HSA and FSA eligible.
Questions people ask
What’s the difference between thyroglobulin and thyroglobulin antibodies?
Thyroglobulin is a protein made by thyroid tissue. After the thyroid is removed for cancer, thyroglobulin in the blood can signal remaining cancer cells, so it’s used as a marker.5 Thyroglobulin antibodies are immune proteins that stick to it and can hide it from the test.5
Do I need both TPO and thyroglobulin antibody tests?
Usually not. TPO antibodies are the better test for thyroid autoimmunity.3,4 A 2014 European pregnancy guideline advises adding thyroglobulin antibodies when TSH is high and TPO antibodies are negative.8 The 2026 ATA guideline limits that to women with a normal but high-ish TSH and a high chance of autoimmunity.4
How long do thyroglobulin antibodies last after thyroid cancer treatment?
They usually fade once the thyroid tissue is gone. In a study of 182 people with thyroid cancer and thyroid antibodies, treated with surgery to remove the whole thyroid and radioactive iodine, thyroglobulin antibodies took a median of about 3 years to disappear, and TPO antibodies about 6.6
Should thyroglobulin antibodies be checked before thyroid cancer surgery?
Not routinely. The 2025 ATA thyroid cancer guideline doesn’t recommend measuring thyroglobulin or its antibodies before surgery.5
Does biotin affect the test?
It can. High-dose biotin, common in hair, skin and nail supplements, interferes with many thyroid tests. Labcorp asks you to stop it at least 72 hours before the draw.1
Often checked alongside
Test details
- Labcorp test
- Thyroglobulin Antibody, 006685
- LOINC
- 8098-6
- Sample
- Blood
- Fasting
- Not needed
- Typical lab range
- 0.0 to 1.4 IU/mL on Labcorp’s newest sample report (August 2026); older reports show 0.0 to 0.92,9
- Units
- IU/mL. Results from different test methods don’t match, so compare results from the same lab.5
Sources
- 1 Labcorp. Thyroglobulin antibody, test 006685. Labcorp test menu. Accessed October 28, 2026. www.labcorp.com/tests/006685/thyroglobulin-antibody
- 2 Labcorp. Sample report, test 042045 (thyroglobulin antibody and thyroglobulin, IMA or LC/MS-MS). Reported August 4, 2026. Accessed October 28, 2026. files.labcorp.com/testmenu-d8/sample_reports/042045_0.pdf
- 3 Garber JR, Cobin RH, Gharib H, et al. Clinical practice guidelines for hypothyroidism in adults: cosponsored by the American Association of Clinical Endocrinologists and the American Thyroid Association. Thyroid. 2012;22(12):1200–1235. doi.org/10.1089/thy.2012.0205
- 4 Korevaar TIM, Leung AM, Alexander EK, et al. American Thyroid Association 2026 guidelines for thyroid disease in preconception, pregnancy, and postpartum. Thyroid. 2026;36(5):481–544. doi.org/10.1177/10507256261445624
- 5 Ringel MD, Sosa JA, Baloch Z, et al. 2025 American Thyroid Association management guidelines for adult patients with differentiated thyroid cancer. Thyroid. 2025;35(8):841–985. doi.org/10.1177/10507256251363120
- 6 Chiovato L, Latrofa F, Braverman LE, et al. Disappearance of humoral thyroid autoimmunity after complete removal of thyroid antigens. Ann Intern Med. 2003;139(5 Pt 1):346–351. doi.org/10.7326/0003-4819-139-5_part_1-200309020-00010
- 7 Osinga JAJ, Liu Y, Männistö T, et al. Risk factors for thyroid dysfunction in pregnancy: an individual participant data meta-analysis. Thyroid. 2024;34(5):646–658. doi.org/10.1089/thy.2023.0646
- 8 Lazarus J, Brown RS, Daumerie C, et al. 2014 European Thyroid Association guidelines for the management of subclinical hypothyroidism in pregnancy and in children. Eur Thyroid J. 2014;3(2):76–94. doi.org/10.1159/000362597
- 9 Labcorp. Sample report, test 006685 (thyroglobulin antibody). Reported February 19, 2024. Accessed October 28, 2026. files.labcorp.com/testmenu-d8/sample_reports/006685.pdf
Updated 28 Oct 2026.
This is general health information, not medical advice: talk to your clinician about your results and before changing any treatment.