Test Code 1020
Test Details
TPO
This assay measures antibodies against thyroid peroxidase (TPO), an enzyme expressed mainly in the thyroid involved in the production of thyroid hormones T3 and T4.
Methodology
Electrochemiluminescence Immunoassay (ECLIA)
Patient Preparation
None
Preferred Specimen
1.0 mL serum collected in a serum separator tube (SST / Tiger Top)
Transport Temperature
Refrigerated (ship on frozen cold packs)
Stability
Refrigerated: 8 days
Lab Values
TPO
- Optimal: <40 IU/mL
- High: ≥40 IU/mL
Clinical Significance
TPO
- Thyroid peroxidase antibody (TPO), is primarily ordered to help diagnose an autoimmune thyroid disease and to distinguish it from other forms of thyroid dysfunction. Abnormal TPO may indicate Graves Disease or Hashimotos.
- Testing may be performed as a follow-up when other thyroid test results such as total or free T3, free T4, and/or TSH indicate thyroid dysfunction.
- A high value usually indicates autoimmune damage to the thyroid due to disorders such as Hashimoto thyroiditis and Graves disease.
- High doses of biotin (> 5 mg/day) may interfere with assay results. Patient assumed to be refraining from biotin supplementation for at least 3 days prior to blood draw.
Treatment Options
TPO
- Treatment is based on etiology of elevation.
- With Graves and Hashimotos, Thyroid hormone replacement therapy is typically necessary when thyroid hormone production becomes significantly decreased and symptoms begin to emerge or worsen. Those with Hashimoto thyroiditis are closely monitored, and thyroid hormone replacement therapy is initiated and/or adjusted as necessary.
