Blood-tests Explained


Disclaimer:

This website is intended to assist with patient education and should not be used as a diagnostic, treatment or prescription service, forum or platform. Always consult your own healthcare practitioner for a more personalised and detailed opinion

Thyroid Antibodies


At a Glance

Why Get Tested?

To help diagnose and monitor autoimmune thyroid diseases and to distinguish these from other forms of thyroid disease; to help guide treatment decisions

When to Get Tested?

When you have an enlarged thyroid (goiter) and/or when your other thyroid tests, such as total or free T3, free T4, and TSH, indicate thyroid dysfunction; along with a thyroglobulin test when your healthcare provider is using it as a monitoring tool; at intervals recommended by your healthcare provider when you have a known autoimmune thyroid disorder

Sample Required?

A blood sample drawn from a vein in your arm

Test Preparation Needed?

None

The Test Sample

What is being tested?

Thyroid autoantibodies are antibodies that develop when a person's immune system mistakenly targets components of the thyroid gland or thyroid proteins, leading to chronic inflammation of the thyroid (thyroiditis), tissue damage, and/or disruption of thyroid function. Laboratory tests detect the presence and measure the quantity of specific thyroid autoantibodies in the blood.

Location of the thyroidThe thyroid is a small, butterfly-shaped gland that lies flat against the windpipe in the throat. The primary hormones that it produces, thyroxine (T4) and triiodothyronine (T3), are vital in helping to regulate the rate at which the body uses energy (metabolism). The body uses a feedback system in which thyroid stimulating hormone (TSH) stimulates the thyroid to produce T4 and T3 as needed. This system helps maintain a relatively stable amount of the thyroid hormones in the blood. When thyroid antibodies interfere with this process, they can lead to chronic conditions and autoimmune disorders associated with hypothyroidism or hyperthyroidism, such as Graves disease or Hashimoto thyroiditis.

Thyroid antibody tests include:

  • Thyroid peroxidase antibody (TPO)
  • Thyroglobulin antibody (TGAb)
  • Thyroid stimulating hormone receptor antibodies (TSHRAb), including thyroid stimulating immunoglobulin (TSI) and thyroid binding inhibitory immunoglobulin (TBII)

For more on these, see the "How is it used?" section.

How is the sample collected for testing?

A blood sample is obtained by inserting a needle into a vein in the arm.

Is any test preparation needed to ensure the quality of the sample?

No test preparation is needed.

The Test