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Thyroperoxidase Antibodies

Item Value
Clinical Questions Does my patient have autoimmune thyroiditis?
Approval req'd? No
Available Stat? No
Test code ATPO
Test group Thyroid tests
Performed by Immunology
In House Availability Friday (day shift)
Method Chemiluminescent Immunoassay
Container type Gold top
Amount to Collect 2 mL blood
Sample type Serum
Preferred volume 1 mL serum
Min. Volume 0.5 mL serum
Processing notes Stored frozen at -20C.
Units U/mL
Normal range
Negative < 60 U/mL
Positive ≥ 60 U/mL
Synonyms anti-TPO antibodies; anti-microsomal antibodies
Turn around times 1-8 days
Additional information The results of this test should be used in conjunction with clinical findings and other laboratory data (such as TSH and thyroid hormone levels) to make a diagnosis of autoimmune thyroid disease (including Hashimoto's thyroiditis and Graves' Disease). Although anti-thyroperoxidase antibodies are a sensitive and specific indicator of autoimmune thyroid disease, a subset of normal individuals may have low level antibodies that may not have clinical significance resulting in a false positive test result. The Manufacturer's guidelines suggest that up to 4-5% of normal individuals may have a positive result with this assay.

The antibody reactivity previously ascribed to the thyroid microsomes is now recognized to be primarily directed against Thyroperoxidase, and is the antibody activity most commonly found in thyroid disease.
LOINC code 8099-4
Last Updated 2/19/2014 4:07:38 PM
Entry Number 921
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