Understanding Thyroid Antibodies: TPO and TG Explained

In conditions like hypothyroidism and hyperthyroidism, antibodies play a crucial role in diagnosing and understanding what is driving the thyroid dysfunction. In this case, in someone with positive thyroid antibodies, we consider this an autoimmune condition or in other words, the body is on high alert and attacking the thyroid gland (read more about thyroid disease HERE!). There are two main types of thyroid antibodies that can be present: Thyroid Peroxidase (TPO) antibodies and Thyroglobulin (TG) antibodies. Let’s break down what these antibodies are and why they matter.

What Are TPO Antibodies?

Thyroid Peroxidase antibodies, often abbreviated as TPOAb or anti-TPO, target an enzyme called thyroid peroxidase. This enzyme is essential for producing thyroid hormones like T4 (thyroxine) and T3 (triiodothyronine), which regulate metabolism, energy levels, and overall bodily functions.

When your immune system mistakenly attacks this enzyme, it can lead to inflammation and damage to the thyroid gland. Elevated TPO antibodies are a hallmark of Hashimoto’s thyroiditis, a common cause of hypothyroidism (or underactive thyroid).

What Are TG Antibodies?

Thyroglobulin antibodies, known as TGAb or anti-TG, attack thyroglobulin—a protein in the thyroid gland that stores thyroid hormones. Like TPO antibodies, these are produced when the immune system is up-regulated and attacks the thyroid gland.

High levels of TG antibodies are also linked to autoimmune thyroid diseases, including Hashimoto’s and sometimes Graves’ disease (which causes hyperthyroidism, or overactive thyroid). They’re less specific than TPO antibodies but can provide additional insights, especially in monitoring thyroid cancer patients after treatment, as thyroglobulin is a tumor marker.

The Significance of Thyroid Antibodies in Thyroid Disease

These antibodies don’t just indicate an autoimmune attack on the thyroid; they help doctors diagnose and manage thyroid disorders early. For instance:

• Diagnosis: Positive TPO or TG antibodies confirm autoimmunity in about 90-95% of Hashimoto’s cases.
• Monitoring: Tracking antibody levels can show disease progression or response to treatment. However, in conventional medicine, antibodies are often never tested and if they are, it is often only checked once and not tracked over time. However, in Functional Medicine the goal should be to reverse or lower these antibody levels which signifies reduction in inflammation and often improvement in thyroid function. 
• Risk Factors: Even if thyroid function is normal, high TPO or TG levels might signal future hypothyroidism, especially in women or those with a family history. This can be a warning sign that we should investigate further to prevent any destruction to the thyroid gland and future need for medication. 

Understanding these antibodies empowers you to take charge of your thyroid health. If you have hypothyroidism but have never had antibody levels checked, now is the time to learn more about your thyroid condition! Book a FREE discovery call below!