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Thyroid Peroxidase Ab (TPOAB)

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EPIC Test Name

THYROID PEROXIDASE ANTIBODY

EPIC Code

LAB858

Specimen Requirements

serum
Minimum Volume:0.5 mL
Collection:Collect specimens using standard laboratory procedures.
Transport:Room Temperature ASAP
Stability:Room Temp: 8 days at 20-25 degrees C
Refrigerated: 8 days at 2-8 degrees C
Frozen: 24 months at -20 degrees C
Container:GOLD
Rejection Causes:Hemolysis,
Insufficient Sample Volume, lipemic samples

Methods

Immunoassay

Turnaround Time

SpecimenFrequency
serumdaily

Reference Ranges

Immunoassay
All RangeUnit
<34 IU/mLIU/mL

Clinical Indications

Thyroperoxidase (TPO) is a heme-containing glycoprotein, located at the apical membrance of the follicular cell of the thyroid gland. TPO has enzymatic activity that catalyzes the oxidation of iodide by hydrogen peroxide, and iodinates and couples tyrosine residues of the thyroglobulin (Tg) for synthesis of thyroid hormone T3 and T4. The hydrogen peroxide is inhibited by excess iodide forming the basis of the Wolff–Chaikoff effect in the treatment of acute hyperthyroidism or “thyroid storm”. Normally, similar to Tg, TSH regulates the synthesis of TPO, therefore thyroid hormone production.
TPO antibody is considered as the most sensitive marker for detecting autoimmune thyroid disease, e.g., Hashimoto thyroiditis, idiopathic myxedema, and Graves disease, and detectable concentrations of anti-TPO antibodies can be seen in most patients with the autoimmune thyroid disorders. In patients with subclinical hypothyroidism that can be identified by testing TSH levels, the presence of TPO antibodies suggests an increased risk in developing overt hypothyroidism.

Additional Information

• Slightly elevated TPO antibodies levels can be found in patients with non-thyroid autoimmune disease, e.g., pernicious anemia, type I diabetes, or other disorders that activate the immune system.
• Human anti-mouse antibodies (HAMA) may be present in samples from patients who have received immunotherapy utilizing monoclonal antibodies or imaging procedure. Caution needs to be given in interpretating the results from patients suspected of having such antibodies.

Common Synonyms

Microsomal Ab

Performed

Lab
Chemistry - Downtown

Interpretative Information

• Elevated TPO antibody values suggest autoimmune thyroiditis, or presence of another autoimmune disease. Diagnosis should be based on clinical findings and other tests if applicable. Healthy subjects (up to 10’s %) were also found to contain anti-thyroid peroxidase (TPO) antibodies.
• The presence of TPO antibodies in subclinical hypothyroidism patients suggest high risk of developing overt hypothyroidism.

CPT

86376

LOINC

8099-4

References

1. Markou K, Georgopoulos N, Kyriazopoulou V, Vagenakis AG. Iodine-Induced hypothyroidism. Thyroid. 2001;11:501-10. PMID: 11396709.
2. Kohno Y, Yamaguchi F, Saito K, Niimi H, Nishikawa T, Hosoya T. Anti-thyroid peroxidase antibodies in sera from healthy subjects and from patients with chronic thyroiditis: differences in the ability to inhibit thyroid peroxidase activities. Clin Exp Immunol 1991;85(3):459-63. PMID: 1893628.
3. Fröhlich E, Wahl R. Thyroid Autoimmunity: Role of Anti-thyroid Antibodies in Thyroid and Extra-Thyroidal Diseases. Front Immunol. 2017;8:521. PMID: 28536577.
4. Gharib H, Tuttle RM, Baskin HJ, Fish LH, Singer PA, McDermott MT. Subclinical thyroid dysfunction: a joint statement on management from the American Association of Clinical Endocrinologists, the American Thyroid Association, and the Endocrine Society. J Clin Endocrinol Metab. 2005;90:581-5; discussion 586-7. PMID: 15643019.
5. Freedman DB, Halsall D, Marshall WJ, Ellervik C: Thyroid disorders. In: Rifai N, Horvath AR, Wittwer CT: eds. Tietz Textbook of Clinical Chemistry and Molecular Diagnostics. 6th ed. Elsevier; 2018:1572-1616

Contact Information

Chemistry - Downtown: (315)464-4460
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