Educational information only. At Precursor, blood testing is requested and reviewed by a clinician and considered alongside your history and other markers, not as a stand-alone diagnosis. Testing is performed in NATA-accredited laboratories to ISO 15189 standards.
What are thyroid peroxidase antibodies?
Thyroid peroxidase antibodies, or TPO antibodies, are immune proteins that target an enzyme the thyroid uses to make its hormones. Their presence suggests the immune system is reacting against the thyroid, which is the hallmark of autoimmune thyroid conditions such as Hashimoto's and Graves' disease.
Why they matter
TPO antibodies help explain the 'why' behind an abnormal thyroid result. When thyroid hormones are shifting, knowing whether antibodies are present tells a clinician whether an autoimmune process is likely driving it, which shapes how the situation is monitored over time.
What your results can mean
Raised
Raised TPO antibodies point toward an autoimmune thyroid process. They can be present before thyroid hormones themselves change, so they are sometimes an early clue, though not everyone with antibodies develops thyroid dysfunction.
Not raised
Low or undetectable TPO antibodies make an autoimmune cause less likely, which is useful context when interpreting the rest of a thyroid panel.
Reference ranges in Australia
TPO antibodies are reported in kilo-international units per litre (kIU/L), with a laboratory-specific cut-off above which they are considered raised. Read your result against the reference value on your own report and in the context of your thyroid hormones.
Test your thyroid with Precursor
TPO antibodies are most meaningful alongside your thyroid hormones. At Precursor, thyroid testing is requested and reviewed by a clinician within Full Advanced Bloods, a single draw covering your thyroid, heart, metabolic, hormonal, kidney, liver and nutrient markers together, so any autoimmune signal is read in full context.
