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Test Code TPO Thyroperoxidase (TPO) Antibody

Important Note

Human anti-mouse antibodies (HAMA) may be present in samples from patients who have received immunotherapy utilizing monoclonal antibodies. Additionally, other heterophile antibodies such as human anti-goat antibodies may be present in patient samples. Manufacturers formulate assays to minimize the effects of these antibodies, however careful evaluation of patient results must be done when patients are known to have such antibodies.

Additional Codes

Powerchart: Thyroperoxidase Antibody (TPO)
MA Cerner: Thyroperoxidase (TPO) Antibodies

Specimen Requirement

0.1 mL Serum or heparin plasma.

Additional Specimen Collection Information

Collection Instructions:
• Minimum volume: 500 mcL serum or heparin plasma
• Hemolysis: does not interfere with this assay
• Lipemia: does not interfere with this assay
• Icterus: does not interfere with this assay
• Storage: Can be stored at room temperature for up to 8 hours. If specimens are stored longer than 8 hours keep refrigerated (2-8C) until transport to the lab.

Reference Value

< 9.0 IU/mL


Testing is performed Monday through Sunday.
Routine: Typically completed within 4 hours after the specimen arrives at the testing site.
STAT: Typically completed within 1 hour after the specimen arrives at the testing site.

CPT Code Information


Test Method

Two Site Immunoassay; Beckman Coulter

Useful For

The principle role of TPO is to catalyze the oxidation of iodide on tyrosine residues in thyroglobulin for the synthesis of T3 and T4 and is one of the most important thyroid gland antigens.

The determination of TPOAb levels is the most sensitive test for detecting autoimmune thyroid disease. The highest TPOAb levels are observed in patients suffering from Hashimoto’s thyroiditis. In this disease, the prevalence of TPOAb is about 90% of cases confirming the autoimmune origin of the disease. These autoantibodies also frequently occur (60-80%) in the course of Graves’ disease.

There is a good association between the presence of autoantibodies against TPO and historical thyroiditis. However, in view of the extensive regenerative capacity of the thyroid under the influence of TSH, chronic thyroid disease may be present for years before the clinical manifestation of hypothyroidism becomes evident, if ever.

The detection of TPOAb is an aid in the diagnosis of thyroid autoimmune disorders and enables the physician to differentiate thyroid autoimmune disorders from non-autoimmune goiter or hypothyroidism.