Lab result explainedThyroidLast updated November 11, 2026

Thyroglobulin test: normal range, what a high level means and what undetectable means after thyroidectomy

Thyroglobulin (Tg) · Thyroid cancer follow-up (ordered with thyroglobulin antibodies and TSH); occasionally with thyroid function tests · reported in ng/mL (equivalent to µg/L)

Thyroglobulin (Tg) is the large storage protein that thyroid cells use to make thyroid hormone, and a small amount leaks into the blood from any thyroid tissue, normal or cancerous. In someone with a thyroid gland, a thyroglobulin level is a rough measure of how much thyroid tissue there is and how active it is: most adults fall between about 1.5 and 38 ng/mL, and a goiter, Graves' disease, thyroiditis or a nodule can push it higher. In that setting the number is rarely important on its own.

The reason most people are tested is different. Papillary and follicular thyroid cancers make thyroglobulin, and after the thyroid has been removed (and often ablated with radioactive iodine), there should be no thyroglobulin left to measure. A result below the assay's detection limit, typically under 0.1 or 0.2 ng/mL, is the single most reassuring finding in thyroid cancer follow-up. A detectable or rising level is the earliest sign that thyroid tissue, benign remnant or recurrent cancer, is still present, usually months to years before anything shows on a scan.

Two things complicate the test. First, thyroglobulin antibodies (TgAb), present in about 20 to 25 percent of people with thyroid cancer, bind thyroglobulin and make the immunoassay read falsely low, so TgAb is always measured on the same sample. Second, results from different manufacturers' assays are not interchangeable, so follow-up is done on the same assay at the same lab wherever possible. The trend over time matters more than any single value, and a thyroglobulin test is not a screening test for thyroid cancer in people who still have a thyroid.

Tg at a glance

What it is: the thyroid's hormone-storage protein; in the blood it acts as a marker of how much thyroid tissue (normal or cancerous) is present.
Normal with an intact thyroid: about 1.5–38 ng/mL (labs differ; some report up to 55 ng/mL). A high value here usually means goiter, thyroiditis, Graves' or a nodule, not cancer.
After total thyroidectomy and radioiodine for thyroid cancer: the goal is undetectable, under 0.1–0.2 ng/mL on a sensitive assay while on levothyroxine; under 1 ng/mL after TSH stimulation is an excellent response.
After thyroidectomy without radioiodine, or after a lobectomy: low stable values (often under 1–5 ng/mL, or under 30 after lobectomy) are expected; a rising trend is what matters.
Thyroglobulin antibodies make the Tg result falsely low; they are always measured alongside, and if positive the TgAb trend is followed instead.
Next step: Tg and TgAb every 6 to 12 months on the same assay, with a neck ultrasound; a detectable, rising or stimulated Tg above 1–2 ng/mL prompts imaging.

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What Tg measures

Thyroglobulin is a 660-kilodalton glycoprotein made only by thyroid follicular cells, where it fills the colloid of each follicle and serves as the scaffold on which iodine is attached and T4 and T3 are assembled. As hormone is released, a little intact thyroglobulin escapes into the circulation. Its level therefore reflects three things: the mass of thyroid tissue, how strongly that tissue is being stimulated by TSH (or by Graves' antibodies), and whether the gland is being injured, since thyroiditis, biopsy, surgery and radioiodine all spill stored thyroglobulin into the blood for days to weeks.

The test is an immunometric assay. Modern second-generation assays detect down to 0.1 ng/mL or lower, which is why 'undetectable' now means under 0.1 to 0.2 ng/mL rather than the under 1 ng/mL of older methods. Because each manufacturer calibrates differently, the same sample can read 30 to 40 percent higher or lower on different platforms; guidelines recommend following a patient on one assay and, when a lab changes its method, re-baselining. Thyroglobulin antibodies interfere by binding the protein and hiding it from the assay antibodies, so a positive TgAb can make a genuinely raised thyroglobulin read as undetectable. Liquid chromatography mass spectrometry (LC-MS/MS) thyroglobulin is less affected and is available at reference labs, though it is less sensitive at very low levels.

Because thyroglobulin production depends on TSH, the level can be measured two ways in cancer follow-up. A basal (suppressed) Tg is taken while you are on levothyroxine with TSH low or normal. A stimulated Tg is taken after TSH has been raised, either by stopping levothyroxine for 3 to 4 weeks or by two injections of recombinant human TSH (Thyrogen), which coaxes any remaining tissue to release thyroglobulin and improves sensitivity. With highly sensitive assays, a basal Tg under 0.2 ng/mL predicts a stimulated Tg under 1 ng/mL in about 98 percent of cases, so stimulated testing is used less than it once was.

Normal range for Tg

Reference ranges vary between labs and by age, sex and pregnancy. Use the range printed on your own report.

Group	Typical range (ng/mL (equivalent to µg/L))	Notes
Adults with an intact thyroid	About 1.5–38 ng/mL	Reference intervals vary by assay; some labs quote up to 55 ng/mL. Smokers, people with goiter and people who are iodine deficient run higher.
Newborns	Up to about 100 ng/mL in the first days	Falls through infancy and childhood; pediatric labs use age-specific ranges.
After total thyroidectomy plus radioiodine (on levothyroxine)	Undetectable, below 0.1–0.2 ng/mL	The target in differentiated thyroid cancer follow-up. 0.2–1 ng/mL is 'indeterminate' and followed; above 1 ng/mL, or rising, is investigated.
After total thyroidectomy plus radioiodine, TSH-stimulated	Below 1 ng/mL	Excellent response in the American Thyroid Association system. 1–10 ng/mL is indeterminate; above 10 ng/mL is a biochemically incomplete response.
After total thyroidectomy without radioiodine (on levothyroxine)	Usually below 1–2 ng/mL, stable	Small remnants of normal thyroid produce a little thyroglobulin. A stable low level is acceptable; a rising level is not.
After lobectomy (half the thyroid removed)	Often up to about 30 ng/mL	Thyroglobulin is much less useful here because the remaining lobe makes it; ultrasound carries the follow-up.
Rising trend in follow-up	Doubling time under 1 year	A thyroglobulin doubling time under 1 year is associated with higher recurrence and mortality risk; over 3 years is low risk.
Thyroglobulin antibodies positive	Tg result unreliable (falsely low)	About 20–25 percent of thyroid cancer patients. TgAb trend becomes the surrogate marker; falling antibodies over 1 to 4 years are reassuring.

High or detectable thyroglobulin

What a high thyroglobulin means depends entirely on whether you still have a thyroid. In someone with an intact gland, a level above the reference range is common and non-specific: a multinodular goiter, Graves' disease, subacute or Hashimoto's thyroiditis, a recent biopsy, iodine deficiency and benign nodules all raise it, and so does thyroid cancer, but with such overlap that the test cannot separate benign from malignant. This is why thyroglobulin is not used to screen for or diagnose thyroid cancer; a nodule is assessed by ultrasound and, if needed, biopsy. The one diagnostic use in people with a thyroid is the opposite direction: a very low or undetectable thyroglobulin in someone who is thyrotoxic points to factitious thyrotoxicosis (taking thyroid hormone) rather than Graves' or thyroiditis.

After total thyroidectomy and radioiodine ablation for papillary or follicular cancer, any detectable thyroglobulin means thyroid tissue is still present. A basal level between 0.2 and 1 ng/mL is indeterminate: in most people it comes from a small benign remnant and either stays flat or slowly falls, and roughly 80 percent will never have a clinically evident recurrence. A level above 1 ng/mL on suppression, a stimulated level above 10 ng/mL, or any value that rises on serial testing is a biochemically incomplete response and is investigated with neck ultrasound and, depending on the level, a radioiodine scan, CT or FDG-PET. Thyroglobulin usually rises months to years before a recurrence can be found on imaging, and a steadily rising level with negative scans is one of the hardest situations in thyroid cancer follow-up; it is managed by watching the trend rather than acting on one number.

Context changes the threshold. Within 4 to 6 weeks of surgery or radioiodine, thyroglobulin is transiently high from tissue injury and should not be interpreted. A TSH that has crept up because the levothyroxine dose is too low will raise thyroglobulin from any remnant. Pregnancy raises it modestly. And heterophile antibodies in the blood can produce a false high on some immunoassays, which is suspected when the level does not fit the clinical picture and is checked by rerunning the sample with blocking reagents or by mass spectrometry.

Common causes

Residual or recurrent differentiated thyroid cancer
Papillary and follicular cancer cells (and Hürthle cell variants) make thyroglobulin. After total thyroidectomy and ablation, a detectable or rising level is the most sensitive signal of persistent disease, often preceding imaging findings by years. Poorly differentiated and anaplastic cancers may make little or none.
Benign thyroid remnant after surgery
Surgeons routinely leave a few milligrams of tissue near the parathyroid glands and recurrent laryngeal nerves. Without radioiodine, this produces a low, stable thyroglobulin (usually under 1 to 2 ng/mL) that is not a sign of recurrence.
Goiter and thyroid nodules
The larger the gland, the more thyroglobulin leaks out; multinodular goiters commonly give levels of 50 to several hundred ng/mL. Benign follicular adenomas also secrete it.
Graves' disease and other hyperthyroidism
TSH receptor antibodies drive the gland hard and raise thyroglobulin, which falls as the disease comes under control. Toxic nodules do the same.
Thyroiditis (subacute, silent, postpartum, Hashimoto's)
Inflamed follicles release their stored thyroglobulin; in subacute thyroiditis levels can be very high for several weeks and then normalize. This is one way to tell thyroiditis from factitious thyrotoxicosis, in which thyroglobulin is suppressed.
Recent biopsy, surgery or radioiodine
Any injury to thyroid tissue spills thyroglobulin. Levels peak in the first days after fine-needle aspiration or radioiodine and may stay raised for 4 to 6 weeks, so cancer follow-up baselines are drawn after that window.
Inadequate TSH suppression or rising TSH
Thyroglobulin output from any remaining tissue is TSH-dependent. A levothyroxine dose that has drifted low, poor absorption, or planned TSH stimulation before a scan will all raise the number.
Iodine deficiency and smoking
Both stimulate the thyroid and raise population thyroglobulin levels; WHO uses median thyroglobulin as a marker of iodine sufficiency in children (a median above 13 ng/mL suggests deficiency).
Pregnancy
hCG stimulates the thyroid and plasma volume changes shift the result; thyroglobulin rises modestly, particularly in iodine-deficient women. Cancer follow-up thresholds are interpreted with this in mind.
Heterophile antibody interference
Human anti-mouse or other heterophile antibodies can bridge the assay antibodies and create a false signal, usually a modest but persistent 'detectable' value that does not fit the picture. Checked by dilution, blocking tubes or mass spectrometry.

Symptoms that can go with it

Usually none; a rising thyroglobulin after thyroid cancer treatment is almost always found before any symptom appears
A new lump or swelling in the neck, or enlarged lymph nodes along the side of the neck, with recurrent disease
Hoarseness, difficulty swallowing or a sense of pressure in the neck if a recurrence presses on the larynx or esophagus
Bone pain or a cough and breathlessness in the uncommon case of distant spread to bone or lung
Neck pain, tenderness and fever with subacute thyroiditis in people who still have a thyroid
Palpitations, tremor, heat intolerance and weight loss when the high level comes from Graves' disease or thyroiditis

Low or undetectable thyroglobulin

After total thyroidectomy and radioiodine for differentiated thyroid cancer, an undetectable thyroglobulin, below 0.1 to 0.2 ng/mL on a sensitive assay with negative thyroglobulin antibodies and a clean neck ultrasound, defines an 'excellent response' in the American Thyroid Association system. The risk of recurrence in this group is about 1 to 4 percent over the following decade, follow-up can be spaced out to every 12 to 24 months, and the levothyroxine dose can usually be relaxed from full suppression to a normal-range TSH. This is the result people hope for, and most people treated for low- and intermediate-risk thyroid cancer achieve it.

The one essential caveat is that an undetectable thyroglobulin is only reassuring if thyroglobulin antibodies are negative. If TgAb is positive, the assay cannot be trusted and the antibody level itself becomes the marker: a TgAb that falls steadily and disappears over 1 to 4 years behaves like an undetectable thyroglobulin, while a TgAb that persists or rises is treated as a possible sign of residual disease and followed with imaging. In people who still have a thyroid, a very low thyroglobulin carries no disease meaning except in one specific situation: thyrotoxicosis with a suppressed thyroglobulin points to someone taking thyroid hormone tablets (deliberately or unknowingly), since every form of thyroid overactivity from the gland itself raises the level.

Common causes

Successful treatment of differentiated thyroid cancer
Total thyroidectomy plus radioiodine ablation removes essentially all thyroglobulin-producing tissue; an undetectable level with negative antibodies is the expected and desired outcome.
Thyroglobulin antibody interference
TgAb binds circulating thyroglobulin and hides it from the immunoassay, producing a falsely low or undetectable reading. Always check the paired TgAb result before taking comfort from a low Tg.
Factitious or exogenous thyrotoxicosis
Levothyroxine or liothyronine from any source (prescribed excess, weight-loss products, contaminated supplements) suppresses TSH and therefore the gland's own thyroglobulin output. High T4 or T3 with a low thyroglobulin is the signature.
Congenital absence of the thyroid (athyreosis)
Newborns with congenital hypothyroidism from an absent gland have undetectable thyroglobulin, which helps distinguish athyreosis from a gland that is present but underactive.
Dedifferentiated or anaplastic tumor
Rarely, a recurrent thyroid cancer loses the ability to make thyroglobulin, so the level stays low despite growing disease; these tumors are usually visible on FDG-PET. This is why follow-up pairs thyroglobulin with ultrasound rather than relying on the blood test alone.

Symptoms that can go with it

None; a low or undetectable thyroglobulin does not cause symptoms
If you still have a thyroid and feel overactive (racing heart, tremor, weight loss) with a low thyroglobulin, that combination itself is the clue and needs discussing
Symptoms of over-replacement with levothyroxine (palpitations, anxiety, insomnia, bone loss over time) can accompany the suppressed TSH used in higher-risk cancer follow-up

Read it alongside

Thyroglobulin antibodies (TgAb) — always measured on the same sample; if positive, the thyroglobulin result is unreliable and the antibody trend is followed instead.
TSH — thyroglobulin output is TSH-driven, so the level is only interpretable alongside the TSH at the time of the draw (suppressed, normal or stimulated).
Free T4 and free T3 — confirm the levothyroxine dose is right and, in people with a thyroid, whether a high thyroglobulin comes with hyperthyroidism.
Neck ultrasound — the imaging partner of thyroglobulin in follow-up; a detectable Tg with a normal ultrasound is watched, a Tg over 10 ng/mL with a normal ultrasound prompts cross-sectional imaging.
Calcitonin — the equivalent marker for medullary thyroid cancer, which does not make thyroglobulin; the two markers follow different cancers.
TSI and TRAb — if a high thyroglobulin in an intact thyroid comes with hyperthyroidism, these confirm or exclude Graves' disease.
TPO antibodies — a high thyroglobulin with positive TPO antibodies and a sore or enlarged gland fits thyroiditis.
Calcium and PTH — checked after thyroidectomy because the parathyroid glands sit against the thyroid and can be bruised or removed.

What usually happens next

If you have had thyroid cancer treatment, ask which response category your result places you in (excellent, indeterminate, biochemically incomplete or structurally incomplete) and whether thyroglobulin antibodies were negative; the two numbers are read together.
Follow-up is typically thyroglobulin and TgAb every 6 to 12 months for the first 1 to 2 years, then every 12 to 24 months if undetectable, with a neck ultrasound at 6 to 12 months and then as risk dictates. Ask that the test stay on the same assay; if the lab changes method, a new baseline is drawn.
A detectable but low basal value (0.2–1 ng/mL) is usually repeated in 6 to 12 months rather than acted on; the question is whether it is flat, falling or rising. Rising values are investigated with ultrasound first, then a diagnostic radioiodine scan, CT or FDG-PET depending on the level.
If TgAb is positive, expect the antibody level to be tracked over years; a steady decline is reassuring and a rise prompts imaging even if thyroglobulin reads undetectable.
If you still have your thyroid and the test was ordered for a nodule or goiter, the number does not decide anything on its own; ultrasound features and, where indicated, a fine-needle biopsy guide what happens next.
Bring a list of supplements and medications: biotin at high doses can interfere with some immunoassays, and any thyroid hormone, including in weight-loss or 'thyroid support' products, changes the result.

Diet, lifestyle and natural levers with evidence

What can move Tg once the cause is known. Nothing here replaces finding the cause.

Nothing natural lowers thyroglobulin in cancer follow-up; consistent testing conditions do matter

Strong evidence

Thyroglobulin after thyroidectomy reflects the amount of thyroid tissue present, and no diet, herb or supplement changes that. What you can control is the quality of the measurement: take levothyroxine consistently so TSH is stable from test to test (a TSH that has drifted from 0.5 to 5 mU/L can double thyroglobulin from a remnant), test at the same lab on the same assay, and wait at least 4 to 6 weeks after surgery, biopsy or radioiodine before a baseline draw.

Stop high-dose biotin before the blood draw

Moderate evidence

Biotin at 5 to 10 mg a day or more (common in hair and nail supplements; the usual multivitamin dose of 30 µg is not a problem) interferes with streptavidin-biotin immunoassays and can produce falsely low or falsely high thyroglobulin, TSH and thyroid hormone results depending on the assay design. The FDA has issued a safety communication on biotin interference. Stopping it 48 to 72 hours before the draw removes the effect.

Do not stop prescribed high-dose biotin (used in some neurological conditions) without telling the prescriber; ask the lab to use a biotin-insensitive method instead.

Adequate, not excessive, iodine

Moderate evidence

In people with an intact thyroid, iodine deficiency raises thyroglobulin: in a trial in iodine-deficient school children, iodine supplementation lowered median thyroglobulin from about 25 to under 10 ng/mL within months, and WHO uses a median under 13 ng/mL as evidence of population iodine sufficiency. The US recommended intake is 150 µg a day (220 µg in pregnancy); iodized salt, dairy, eggs and seafood supply it. This is only relevant to the interpretation of a mildly high thyroglobulin in someone who still has a thyroid.

High-dose iodine or kelp supplements (over 500 to 1,000 µg a day) can trigger both hypothyroidism and hyperthyroidism in people with thyroid disease, and a low-iodine diet is specifically required for 1 to 2 weeks before radioiodine scans or treatment; follow your team's instructions.

Do not smoke

Moderate evidence

Thiocyanate from cigarette smoke competes with iodine uptake and stimulates the thyroid, and population studies consistently find smokers have higher thyroglobulin (by around 20 to 40 percent) and larger glands than non-smokers, with levels falling after quitting. Smoking also roughly doubles the risk of Graves' disease and thyroid eye disease. There is no evidence it changes thyroglobulin after thyroidectomy.

Selenium for autoimmune thyroiditis (indirect)

Preliminary evidence

In people with Hashimoto's thyroiditis, 200 µg a day of selenium for 3 to 12 months lowered TPO antibody levels by about 20 to 40 percent in several randomized trials and meta-analyses, and in some lowered thyroglobulin antibodies too, which matters indirectly because TgAb interferes with the thyroglobulin assay. There is no good evidence that selenium lowers thyroglobulin itself or affects thyroid cancer outcomes.

Doses above 400 µg a day cause toxicity (hair loss, nail changes, nausea), and a large trial linked long-term 200 µg supplementation to a higher risk of type 2 diabetes; check your diet first, since two Brazil nuts supply roughly 200 µg.

When to see a clinician promptly

A rising thyroglobulin on two consecutive tests after thyroid cancer treatment, or a basal level above 1 ng/mL or stimulated level above 10 ng/mL, needs review with your endocrinologist and imaging; it is not an emergency, but it should not wait for the next routine visit.
A new lump in the neck, enlarged neck lymph nodes, new hoarseness or difficulty swallowing after thyroid cancer treatment, whatever the thyroglobulin shows.
New persistent bone pain, an unexplained cough or breathlessness in someone with a history of thyroid cancer, which can signal distant spread.
Palpitations, a racing or irregular heartbeat, severe anxiety, tremor or unexplained weight loss, which may mean your levothyroxine dose is too high or, in someone with a thyroid, hyperthyroidism; a resting heart rate persistently above 120, chest pain or fainting needs same-day care.
Tingling around the mouth or in the fingers, or muscle cramps and spasms, in the weeks after thyroidectomy: possible low calcium from parathyroid injury, which needs prompt blood tests.
Any thyroglobulin test ordered because of a thyroid nodule should be followed by a discussion of ultrasound findings, not the thyroglobulin number; ask what the next step for the nodule is.

Frequently asked questions

What is a normal thyroglobulin level?

With a thyroid gland in place, most adults measure about 1.5 to 38 ng/mL, with some labs quoting up to 55; the exact interval depends on the assay. After total thyroidectomy and radioiodine for thyroid cancer, 'normal' is undetectable, below 0.1 to 0.2 ng/mL on a sensitive assay. After thyroidectomy without radioiodine, a stable level under 1 to 2 ng/mL is typical, and after a lobectomy up to about 30 ng/mL is expected because half the gland remains.

What does thyroglobulin undetectable mean?

It means the assay found no thyroglobulin above its detection limit, usually 0.1 or 0.2 ng/mL. After thyroid cancer surgery and ablation, an undetectable level with negative thyroglobulin antibodies and a normal neck ultrasound is an 'excellent response', with a recurrence risk of roughly 1 to 4 percent over the next decade. If thyroglobulin antibodies are positive, an undetectable thyroglobulin cannot be trusted on its own, and the antibody trend is followed instead.

What level of thyroglobulin indicates cancer recurrence?

There is no single number, but the American Thyroid Association treats a basal (on levothyroxine) thyroglobulin above 1 ng/mL, a TSH-stimulated level above 10 ng/mL, or a rising trend on serial tests as a 'biochemically incomplete response' that warrants imaging. Values of 0.2 to 1 ng/mL are indeterminate and usually just repeated. A thyroglobulin doubling time under a year is the most worrying pattern. Many people with a detectable but stable low level never develop a visible recurrence.

Can thyroglobulin be high without cancer?

Yes, very commonly. In someone with a thyroid, goiter, thyroid nodules, Graves' disease, thyroiditis, iodine deficiency, smoking, pregnancy and a recent biopsy all raise thyroglobulin, often to levels higher than those seen in cancer. That overlap is why it is not used to diagnose thyroid cancer or to decide whether a nodule is benign. After thyroidectomy, a small benign remnant of normal thyroid tissue also produces a low, stable level.

What is the difference between thyroglobulin and thyroglobulin antibodies?

Thyroglobulin is the thyroid protein itself; thyroglobulin antibodies (TgAb) are immune proteins directed against it, found in Hashimoto's, Graves' and about a quarter of thyroid cancer patients. They are always measured together after thyroid cancer because the antibodies bind thyroglobulin and make its level read falsely low. A positive TgAb does not mean cancer has come back, but it does mean the thyroglobulin number is unreliable and the antibody level is tracked instead.

Why is my thyroglobulin going up after thyroidectomy?

The common explanations are a benign remnant responding to a TSH that is no longer suppressed (for example after a levothyroxine dose reduction or missed doses), a change of lab or assay (results can differ 30 to 40 percent between methods), pregnancy, or a test drawn within a few weeks of surgery or radioiodine. If none of those apply and the rise is confirmed on repeat, residual or recurrent thyroid tissue is assumed and a neck ultrasound and further imaging are arranged. The rate of rise matters more than the absolute value.

What is a stimulated thyroglobulin test?

Thyroglobulin release depends on TSH, so raising TSH makes any remaining thyroid tissue easier to detect. This is done either by stopping levothyroxine for 3 to 4 weeks (which causes temporary hypothyroid symptoms) or by two injections of recombinant TSH (Thyrogen) on consecutive days with blood drawn on day 5. A stimulated level under 1 ng/mL is an excellent response. With modern sensitive assays, an undetectable basal thyroglobulin predicts a low stimulated value so reliably that stimulation is now used selectively.

Do I need to fast or stop levothyroxine for a thyroglobulin test?

No fasting is needed and you should keep taking levothyroxine as usual unless your clinician has specifically arranged a withdrawal-stimulated test. Take the tablet at your normal time; what matters is that your TSH is in the same range at each follow-up test. Stop high-dose biotin supplements for 2 to 3 days beforehand, mention any thyroid-containing supplements, and avoid testing within 4 to 6 weeks of thyroid surgery, biopsy or radioiodine.

References

Thyroglobulin test. MedlinePlus, US National Library of Medicine (2023)View source
Haugen BR, Alexander EK, Bible KC, et al.. 2015 American Thyroid Association management guidelines for adult patients with thyroid nodules and differentiated thyroid cancer. Thyroid (2016)View source
Spencer C, Fatemi S. Thyroglobulin (Tg) testing revisited: Tg assays, TgAb assays, and correlation of results with clinical outcomes. Journal of Clinical Endocrinology and Metabolism (2013)
Giovanella L, Clark PM, Chiovato L, et al.. Clinical utility of highly sensitive thyroglobulin assays in differentiated thyroid cancer. European Journal of Endocrinology (2014)
Miyauchi A, Kudo T, Miya A, et al.. Thyroglobulin doubling time predicts recurrence of differentiated thyroid cancer. Thyroid (2011)
Chiovato L, Latrofa F, Braverman LE, et al.. Thyroglobulin antibodies in thyroid cancer: clinical significance of their changes after therapy. Annals of Internal Medicine (2003)
Ma ZF, Skeaff SA. Thyroglobulin as a biomarker of iodine deficiency: a review. Thyroid (2014)
The FDA warns that biotin may interfere with lab tests: FDA safety communication. US Food and Drug Administration (2019)
Thyroid cancer. Merck Manual Professional Version (2024)
Thyroid cancer treatment (PDQ): health professional version. National Cancer Institute (2024)View source
van Zuuren EJ, Albusta AY, Fedorowicz Z, Carter B, Pijl H. Selenium supplementation for Hashimoto's thyroiditis: summary of a Cochrane systematic review. European Thyroid Journal (2014)
Baloch Z, Carayon P, Conte-Devolx B, et al.. Laboratory medicine practice guidelines: laboratory support for the diagnosis and monitoring of thyroid disease. Thyroid (2003)

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This page is educational and is not medical advice or a diagnosis. Lab results have to be interpreted together with your history, symptoms and other results by a clinician who knows you. Do not start or stop a supplement to change a lab value before the cause is known.