What is Anti-TPO?
Thyroid peroxidase (TPO)antibody test measures anti thyroperoxidase antibodies in your blood. The body produces these antibodies when cells in your thyroid become damaged. These antibodies can be a sign of autoimmune diseases that cause the thyroid to make too much or little thyroid hormone.Having antithyroid antibodies in your blood doesn’t automatically mean you have a thyroid disease. However, you may be at an increased risk for thyroid disease in the future. If your test is positive, it means that antibodies are present in your blood which could indicate that there is an autoimmune condition affecting your thyroid gland.Why is Anti-TPO done?
To diagnose autoimmune disorders of thyroid like Hashimoto’s thyroiditis (swelling of thyroid gland resulting in decreased thyroid function), Grave’s disease (overactive thyroid gland resulting in overproduction of thyroid hormones) or idiopathic myxedema (associated with low levels of thyroid hormones)

To differentiate between autoimmune disorders of thyroid from non-autoimmune disorders such as goiter or hypothyroidism.

To diagnose chronic thyroiditis

To diagnose subclinical hypothyroidism

What does Anti-TPO Measure?
TPO is also known as thyroid peroxidase or iodide peroxidase which is an enzyme mainly expressed in the thyroid gland. The thyroid gland is positioned at the lower part of the neck. TPO is found in the cells of the thyroid follicle where it helps in the production of the thyroid hormones. Its basic function is to oxidize iodide ions to form iodine atoms which assist in the production of thyroxine (T4) or triiodothyronine (T3), the thyroid hormones. TPO is an antigenic determinant of autoantibodies in diseases like autoimmune disorders of the thyroid. These antibodies are called as anti-TPO antibodies (anti-Thyroid peroxidase antibodies) which activates complement and might be associated with dysfunction of thyroid and its pathogenesis. To assess these antibodies, Anti-TPO antibody test is carried out.