Thyroid Antibodies (TPO + TgAb)

Also known as: TPOAb, Thyroglobulin Antibody

Autoantibodies against thyroid peroxidase and thyroglobulin — markers of autoimmune thyroid disease.

Hashimoto's is the most common cause of hypothyroidism in developed countries, and antibodies appear years before TSH moves. Testing them explains 'why' and predicts trajectory. Far more common in women.

Standard — male
TPO <9 IU/mL · TgAb <4 IU/mL (assay dependent)
★ Optimal — male
Negative/undetectable.
Standard — female
Same thresholds — but prevalence is 5–8× higher in women
★ Optimal — female
Negative. Positive antibodies with a normal TSH means monitoring, not immediate treatment.
🔍 Why it happensAutoimmune predisposition, genetics, gluten sensitivity/celiac (associated), selenium deficiency, excess iodine, EBV and other infections, postpartum period, and high stress.
▲ If Thyroid Antibodies (TPO + TgAb) is highAutoimmune thyroid disease. Predicts progression to overt hypothyroidism — worth monitoring TSH annually even if currently normal.
▼ If Thyroid Antibodies (TPO + TgAb) is lowNormal.

The plan of attack

In this order. Most people start at step four, which is why they change five things at once and learn nothing.

  1. Confirm the number is real
    Biotin (B7). Biotin interferes with the streptavidin-biotin immunoassays most hormone tests run on. Depending on the assay design it pushes the result falsely HIGH or falsely LOW — there is no single direction to correct for. Hair, skin and nail products are the usual source, and doses in those are far above the RDA. Stop biotin 48–72 hours before the draw, and check every supplement label rather than just the one labelled biotin.
  2. Read it with its partner
    Test once if you have any thyroid symptoms or family history — it changes the interpretation of every future thyroid panel. Draw it alongside: TSH (Thyroid-Stimulating Hormone), Free T4 (Thyroxine), Free T3 (Triiodothyronine).
  3. Work out which direction is yours
    If it's high — Autoimmune thyroid disease. Predicts progression to overt hypothyroidism — worth monitoring TSH annually even if currently normal.
    If it's low — Normal.
  4. Fix it in this order
    Nutrition. Selenium-rich foods (Brazil nuts). Screen for celiac disease — there's a well-documented association with autoimmune thyroid disease. Avoid excess iodine, which can drive antibody production higher.
    Lifestyle. Manage stress, prioritize sleep, address gut health. Antibody levels often fluctuate with overall inflammatory load.
    Supplements. Selenium has RCT evidence for reducing TPO antibody titers. Vitamin D (commonly low in autoimmunity), and myo-inositol combined with selenium shows promise in trials.
    Hormones. Positive antibodies with normal TSH = monitor. Treatment begins when thyroid function actually declines — that's a physician's call.
    Compounds. No peptide application, though systemic inflammation reduction may help overall.
    Work down the list, not across it. Adding a compound on top of an unfixed diet is why generic protocols fail.
  5. Retest
    Annually if positive; TSH monitoring matters more than repeat antibody titers. Change one thing at a time, or the retest can't tell you which thing worked.

How to fix it

🥩 Nutrition: Selenium-rich foods (Brazil nuts). Screen for celiac disease — there's a well-documented association with autoimmune thyroid disease. Avoid excess iodine, which can drive antibody production higher.
💊 Supplements: Selenium 200 mcg/day has RCT evidence for reducing TPO antibody titers. Vitamin D (commonly low in autoimmunity), and myo-inositol combined with selenium shows promise in trials.
🏃 Lifestyle: Manage stress, prioritize sleep, address gut health. Antibody levels often fluctuate with overall inflammatory load.
⚕️ Hormones / medications: Positive antibodies with normal TSH = monitor. Treatment begins when thyroid function actually declines — that's a physician's call.
🧬 Peptides: No peptide application, though systemic inflammation reduction may help overall.
⚡ Testing tip / TRT noteTest once if you have any thyroid symptoms or family history — it changes the interpretation of every future thyroid panel.
Retest: Annually if positive; TSH monitoring matters more than repeat antibody titers.
Run alongside: TSH · Free T4 · Free T3 · Vitamin D · Selenium

📚 Toulis KA et al., Thyroid 2010 — selenium supplementation and TPO antibodies meta-analysis.

🩸 Test your Thyroid Antibodies (TPO + TgAb)

Order directly through Marek Diagnostics — no doctor's visit needed, drawn at any Quest location in the US. Code CAMERON applies 10% off automatically.

Order this test — 10% off → Browse all 102 markers →

What Thyroid Antibodies (TPO + TgAb) is usually tested alongside

On its own, one marker is a data point. These panels include Thyroid Antibodies (TPO + TgAb) plus the markers that make it interpretable — each names every test, why it is on the list, and loads the whole set into your cart in one click at 10% off.

🛡️ Autoimmune Screen $183.15
includes this + 8 more markers — Joint pain, unexplained rashes, recurring low-grade fevers, profound fatigue, or a family history of autoimmune disease.
🦋 Thyroid Deep Dive $185.40
includes this + 7 more markers — Fatigue, cold intolerance, weight change, hair loss, constipation, low mood, or a 'normal TSH' that never explained how you feel. Women are 5–8x more likely to be affected.
🍼 Postpartum Recovery $146.70
includes this + 8 more markers · built for women — Anywhere from 6 weeks to 18 months after giving birth, especially with exhaustion, hair shedding, mood changes, or a sense that you haven't bounced back.

What moves your Thyroid Antibodies (TPO + TgAb)

3 supplements in the Vault have a documented effect on this marker, or are a reason to have measured it first:

Iodine — High-dose iodine can precipitate or worsen autoimmune thyroiditis
Selenium — The best-evidenced use is lowering TPO antibodies
Thyroid Support — Iodine can accelerate autoimmune thyroid disease. Know before you start

Browse all 237 compounds & 350 supplements →

Would you feel it? Symptoms Thyroid Antibodies (TPO + TgAb) helps explain

People rarely search for a marker — they search for how they feel. These are the complaints where this marker is worth checking, and whether it is a first-line test or a follow-up once the obvious causes are ruled out.

🦋 Thyroid nodule, thyroid disease in the family, or already on thyroid medstest first🤰 Trying to conceive, or pregnancy questionstest first💇 Hair thinning or sheddingthen♀️ Irregular periods / PMS / fertility issuesthen

Why your Thyroid Antibodies (TPO + TgAb) might be wrong

Most abnormal results are interference, not disease. These are the things that measurably move this specific marker — check them before you change anything. Each one says whether the number is wrong and should be repeated, badly timed and should be redrawn, or real with a cause worth explaining.

🔬 Biotin (B7)The number is wrong — repeat it

Biotin interferes with the streptavidin-biotin immunoassays most hormone tests run on. Depending on the assay design it pushes the result falsely HIGH or falsely LOW — there is no single direction to correct for. Hair, skin and nail products are the usual source, and doses in those are far above the RDA.

Stop biotin 48–72 hours before the draw, and check every supplement label rather than just the one labelled biotin.

🔬 Assay-to-assay variationThe number is wrong — repeat it

TPO and thyroglobulin antibody titres are not standardised between manufacturers. A value of 300 at one lab is not the same as 300 at another, so a 'rise' can be a change of lab.

Track antibodies at the same lab or not at all. Positive vs negative is the reliable read; the exact number is not.

🏃 Postpartum periodA real change — retest once it passes

Antibody titres shift substantially in the year after delivery as the immune system rebounds.

Interpret postpartum results against the delivery date.

What Thyroid Antibodies (TPO + TgAb) means in combination

A single marker tells you a little. Combinations tell you the story — these are the named patterns this marker takes part in, and what each one points at.

Autoimmune thyroid before the thyroid stops working
TPO antibodies positive · Thyroglobulin antibodies positive · TSH still normal

Antibodies typically precede dysfunction by years. A normal TSH today does not mean nothing is happening — it means the gland is still compensating.

This is the window where it is worth acting. Monitor TSH and Free T4 every 6–12 months, ensure selenium is adequate, and address gut and vitamin D status. The Autoimmune Thyroid protocol covers the evidence and the noise.

What to test next

Markers rarely answer alone. These are the ones that put Thyroid Antibodies (TPO + TgAb) in context — each with its own full breakdown.

Frequently asked questions

What is a normal Thyroid Antibodies (TPO + TgAb) level?

TPO <9 IU/mL · TgAb <4 IU/mL (assay dependent) Ranges vary by laboratory and assay — always compare to the range printed on your own report.

What is the optimal Thyroid Antibodies (TPO + TgAb) level?

Negative/undetectable.

What causes high Thyroid Antibodies (TPO + TgAb)?

Autoimmune thyroid disease. Predicts progression to overt hypothyroidism — worth monitoring TSH annually even if currently normal.

What causes low Thyroid Antibodies (TPO + TgAb)?

Normal.

How do I test Thyroid Antibodies (TPO + TgAb)?

You can order Thyroid Antibodies (TPO + TgAb) directly through Marek Diagnostics without a doctor's visit — drawn at any Quest Diagnostics location in the US. Code CAMERON applies 10% off automatically.

Important: This page is education only. The ranges shown are published reference and functional ranges from the cited literature — not a diagnosis and not medical advice. Lab ranges vary by assay and laboratory; always compare against the range printed on your own report and discuss your results with a qualified healthcare provider.