Thyroid Panel and Anti-TPO Antibody

Please review Order Guide: TSH, T3, T4, rT3 for information on basic thryoid testing. The following section contains information on auto-immune hypothroidism and anti-TPO antibody testing.

What are the types of hypothyroidism?

• Auto-immune hypothyroidism (AKA Hashimoto’s Disease)

• Hypothyroidism due to iodine deficiency

• Drug-induced hypothyroidism (i.e. amiodarone or lithium)

• Hypothyroidism after radiation treatment

• Central hypothrydoisim (rare - i.e. pituitary apoplexy, surgery, radiation, drug-induced)

What is the most common cause of hypothyroidism in Canada?

Auto-immune hypothyroidism(AKA Hashimoto’s Disease) is the most common form of hypothyroidism in Canada. Iodine is a necessary nutrient to make thyroid hormone. In Canada, people generally have an adequate dietary intake of iodine through fortified foods (i.e. iodine-fortified table salt). Outside of developed countries like Canada, iodine deficiency is the most common cause of hypothyroidism.

What is Hashimoto’s Disease?

Hashimoto’s Disease or Auto-immune hypothyroidism (the most common cause of hypothyroidism in Canada) occurs because your body’s immune system begins attacking its own thyroid gland. The immune system starts making antibodies to a component of your thyroid gland called Thyroid-Peroxidase and Thyroglobulin, causing it to become non-functional. These are called Anti-TPO Antibodies and Anti-Thyroglobulin Antibodies. Approximately 10% of people with Hashimoto’s Thyroiditis can be antibody negative however.

What are anti-TPO Antibodies?

Anti-TPO antibodies when measured high, in the presence of an elevated TSH and low T4 suggest Auto-immune Hypothyroidism. Most guidelines do not recomment routine testing with anti-TPO antibodies as they are not necessary to make a diagnosis of hypothyroidism.

Does TeleTest offer anti-TPO Antibody?

We currently only offer a standard thyroid panel, which checks TSH, Free T3(FT3), Free T4(FT4), and Reverse T3(rT3) to assess thyroid function. This panel is primarily used to monitor your thyroid levels, especially if you are currently on thyroid medication.

TPO antibodies(TPOAb) are used to help evaluate autoimmune thyroid conditions(like Hashimoto’s thyroiditis), and they aren’t included in our standard panel at this time.

If you’re specifically looking to check TPOAb, we recommend speaking with your family doctor or local walk-in clinic, who can order that test separately if appropriate.

When is ordering an anti-TPO antibody useful?

If you have a TSH between 4 and 10, with a normal Free T4, having anti-TPO antibodies can guide a physician to start treatment. A negative anti-TPO antibody might mean a doctor will monitor your TSH without starting medications if your TSH is between 4-10.

I have a positive anti-TPO Antibody. Do I need to re-measure anti-TPO antibodies?

Auto-immune thyroiditis (Hashimoto’s disease) is a chronic condition and repeat measurement is not necessary.