Thyroid
TPO Antibodies (Thyroid Peroxidase)
Thyroid
Autoimmune thyroid marker. Elevated in Hashimoto's thyroiditis and Graves' disease.
VAT-exempt medical service
Thyroid peroxidase (TPO) is an enzyme essential for the production of thyroid hormones. When the immune system mistakenly produces antibodies against TPO, it can lead to chronic inflammation, tissue damage, and disrupted thyroid function. Anti-TPO antibodies are the hallmark of autoimmune thyroid disease and are found in the vast majority of Hashimoto's thyroiditis cases and a significant proportion of Graves' disease patients.
TPO antibody testing is crucial for determining whether a thyroid condition has an autoimmune origin. It is recommended when thyroid function tests are abnormal, when you have symptoms despite normal TSH and T4, during pregnancy (about 20% of pregnant women have elevated TPO antibodies unknowingly), and if you have a personal or family history of autoimmune or thyroid disorders. Tracking antibody levels over time can also help monitor disease progression and response to treatment.
What a high value can mean
A positive (elevated) TPO antibody result indicates that the immune system is producing antibodies against the thyroid. The higher the level, the more likely an autoimmune thyroid disorder is present. Hashimoto's thyroiditis is the most common association, typically presenting with hypothyroidism (high TSH, low-to-normal T4 and T3). Elevated TPO antibodies may also appear in Graves' disease and other autoimmune conditions.
What a low value can mean
A negative or low TPO antibody result means antibodies were not detected at clinically significant levels at the time of testing. This makes autoimmune thyroid disease less likely but does not completely rule it out, as some patients with autoimmune thyroiditis do not produce detectable antibodies. Retesting may be warranted if symptoms persist.
No preparation is required for this test. Bring valid identification to your appointment. If you take a supplement containing biotin (often sold for hair and nails), pause it for two days before the test, as high doses can distort the result.
Order your test
Choose your test and pay online. Your lab referral is created straight away.
Give your sample
Visit any of our partner sampling locations. No appointment needed at most of them.
The lab analyses it
Your sample is analysed at an accredited Swedish laboratory.
Get your results
Your values appear in your account with reference ranges and an explanation of each marker.
TPO antibodies target thyroid peroxidase, an enzyme involved in hormone production, while TG (thyroglobulin) antibodies target thyroglobulin, a protein that stores thyroid hormones. Both are markers of autoimmune thyroid disease and are often tested together for a comprehensive assessment.
Yes. Some individuals test positive for TPO antibodies but have normal thyroid function. However, they carry an increased risk of developing thyroid disease in the future, making periodic monitoring advisable.
Some research suggests that reducing inflammation through dietary changes, stress management, and addressing nutrient deficiencies (such as selenium and vitamin D) may help lower antibody levels over time, though individual results vary.
Elevated TPO antibodies during pregnancy are associated with a higher risk of miscarriage, preterm birth, and postpartum thyroiditis. Early detection allows for closer monitoring and timely intervention.