High (Positive) Anti TPO Antibodies:
A positive TPO antibody result supports the diagnosis of autoimmune thyroiditis, such as Hashimoto’s thyroiditis, and may also be present in Graves’ disease. It is recommended measuring TPO antibodies once to diagnose autoimmune thyroid disease when thyroid dysfunction is suspected.
Low or Absent Anti TPO Antibodies:
A negative result makes autoimmune thyroiditis less likely, particularly when thyroid function tests (TFTs) are normal. TPO antibodies should not be tested when TFTs are normal, implying limited clinical significance in the absence of thyroid dysfunction.
