Test Id : TPO
Thyroperoxidase Antibodies, Serum
Useful For
Suggests clinical disorders or settings where the test may be helpful
Aiding in the diagnosis of thyroid autoimmune disorders
Differentiating thyroid autoimmune disorders from nonautoimmune goiter or hypothyroidism
As a diagnostic tool in deciding whether to treat a patient who has subclinical hypothyroidism
Testing Algorithm
Delineates situations when tests are added to the initial order. This includes reflex and additional tests.
For more information, see Thyroid Function Ordering Algorithm
Method Name
A short description of the method used to perform the test
Chemiluminometric Immunoassay
NY State Available
Indicates the status of NY State approval and if the test is orderable for NY State clients.
Reporting Name
Lists a shorter or abbreviated version of the Published Name for a test
Aliases
Lists additional common names for a test, as an aid in searching
Hashimoto Disease
Microsomal Antibodies
Thyroid Antibody Group
Thyroid Peroxidase Antibody
Thyroperoxidase Antibody, Serum
TPO (Thyroperoxidase) Antibodies
Thyroid Microsomal Antibodies
Antithyroid Antibodies
Testing Algorithm
Delineates situations when tests are added to the initial order. This includes reflex and additional tests.
For more information, see Thyroid Function Ordering Algorithm
Specimen Type
Describes the specimen type validated for testing
Serum Red
Specimen Required
Defines the optimal specimen required to perform the test and the preferred volume to complete testing
Patient Preparation: For 12 hours before specimen collection, patient should not take multivitamins or dietary supplements (eg, hair, skin, and nail supplements) containing biotin (vitamin B7).
Supplies: Sarstedt 5 mL Aliquot Tube (T914)
Collection Container/Tube: Red top
Submission Container/Tube: Plastic vial
Specimen Volume: 0.6 mL serum
Collection Instructions: Within 2 hours of collection, centrifuge and aliquot serum into plastic vial.
Special Instructions
Library of PDFs including pertinent information and forms related to the test
Specimen Minimum Volume
Defines the amount of sample necessary to provide a clinically relevant result as determined by the testing laboratory. The minimum volume is sufficient for one attempt at testing.
Serum: 0.5 mL
Reject Due To
Identifies specimen types and conditions that may cause the specimen to be rejected
| Gross hemolysis | Reject |
| Gross lipemia | OK |
Specimen Stability Information
Provides a description of the temperatures required to transport a specimen to the performing laboratory, alternate acceptable temperatures are also included
| Specimen Type | Temperature | Time | Special Container |
|---|---|---|---|
| Serum Red | Refrigerated (preferred) | 7 days | |
| Ambient | 7 days | ||
| Frozen | 30 days |
Useful For
Suggests clinical disorders or settings where the test may be helpful
Aiding in the diagnosis of thyroid autoimmune disorders
Differentiating thyroid autoimmune disorders from nonautoimmune goiter or hypothyroidism
As a diagnostic tool in deciding whether to treat a patient who has subclinical hypothyroidism
Testing Algorithm
Delineates situations when tests are added to the initial order. This includes reflex and additional tests.
For more information, see Thyroid Function Ordering Algorithm
Clinical Information
Discusses physiology, pathophysiology, and general clinical aspects, as they relate to a laboratory test
Thyroperoxidase (TPO) is an enzyme involved in thyroid hormone synthesis, catalyzing the oxidation of iodide on tyrosine residues in thyroglobulin for the synthesis of triiodothyronine and thyroxine (tetraiodothyronine). TPO is a membrane-associated hemo-glycoprotein expressed only in thyrocytes and is one of the most important thyroid gland antigens.
Disorders of the thyroid gland are frequently caused by autoimmune mechanisms with the production of autoantibodies. Anti-TPO antibodies activate complement and are thought to be significantly involved in thyroid dysfunction and the pathogenesis of hypothyroidism.
The determination of TPO antibody levels is the most sensitive test for detecting autoimmune thyroid disease (eg, Hashimoto thyroiditis, idiopathic myxedema, and Graves disease), and detectable concentrations of anti-TPO antibodies are observed in most patients with these disorders. The highest TPO antibody levels are observed in patients suffering from Hashimoto thyroiditis. In this disease, the prevalence of TPO antibodies 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.
In patients with subclinical hypothyroidism, the presence of TPO antibodies is associated with an increased risk of developing overt hypothyroidism. Many clinical endocrinologists use the TPO antibody test as a diagnostic tool in deciding whether to treat a patient with subclinical hypothyroidism, and Mayo Clinic Laboratories endorses this practice.
For more information, see Thyroid Function Ordering Algorithm.
Reference Values
Describes reference intervals and additional information for interpretation of test results. May include intervals based on age and sex when appropriate. Intervals are Mayo-derived, unless otherwise designated. If an interpretive report is provided, the reference value field will state this.
<9.0 IU/mL
Reference values apply to all ages.
Interpretation
Provides information to assist in interpretation of the test results
Values above 9.0 IU/mL are generally associated with autoimmune thyroiditis, but elevations are also seen in other autoimmune diseases.
In patients with subclinical hypothyroidism, the presence of thyroperoxidase (TPO) antibodies predicts a higher risk of developing overt hypothyroidism, 4.3% per year versus 2.1% per year in antibody-negative individuals. Furthermore, it raises the concern that such patients may be at increased risk of developing other autoimmune diseases, such as adrenal insufficiency and type 1 diabetes.
The frequency of detectable anti-TPO observed in nonimmune thyroid disease is similar to the 10% to 12% observed in a healthy population with normal thyroid function.
There is a good association between the presence of autoantibodies against TPO and histological thyroiditis. However, in view of the extensive regenerative capacity of the thyroid under the influence of thyrotropin, chronic thyroid disease may be present for years before the clinical manifestation of hypothyroidism becomes evident, if ever.
Cautions
Discusses conditions that may cause diagnostic confusion, including improper specimen collection and handling, inappropriate test selection, and interfering substances
Moderately increased levels of thyroperoxidase antibodies may be found in patients with a non-thyroid autoimmune disease such as pernicious anemia, type I diabetes, or other disorders that activate the immune system.
Some patients who have been exposed to animal antigens, either in the environment or as part of treatment or imaging procedure, may have circulating anti-animal antibodies present. These antibodies may interfere with the assay reagents to produce unreliable results.
Clinical Reference
Recommendations for in-depth reading of a clinical nature
1. Feldt-Rasmussen U. Analytical and clinical performance goals for testing autoantibodies to thyroperoxidase, thyroglobulin, and thyrotropin receptor. Clin Chem. 1996;42(1):160-163
2. Gharib H, Tuttle RM, Baskin HJ, et al. Consensus Statement #1: Subclinical thyroid dysfunction: a joint statement on management from the American Association of Clinical Endocrinologists, the American Thyroid Association, and the Endocrine Society. Thyroid. 2005;15(1):24-28. doi:10.1089/thy.2005.15.24
3. Frohlich E, Wahl R. Thyroid Autoimmunity: Role of Anti-thyroid Antibodies in Thyroid and Extra-Thyroidal Diseases. Front Immunol. 2017;8:521. Published 2017 May 9. doi:10.3389/fimmu.2017.00521
4. 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
Method Description
Describes how the test is performed and provides a method-specific reference
The Access TPO (thyroperoxidase) antibody assay is a sequential 2-step immunoenzymatic (sandwich) assay. A sample is added to a reaction vessel with paramagnetic particles coated with thyroperoxidase protein. The serum TPO antibody binds to thyroperoxidase. After incubation in a reaction vessel, materials bound to the solid phase are held in a magnetic field while unbound materials are washed away. Protein A-alkaline phosphatase conjugate is added and binds to the TPO antibody. After the second incubation, materials bound to the solid phase are held in a magnetic field while unbound materials are washed away. The chemiluminescent substrate Lumi-Phos 530 is added to the vessel and light generated by the reaction is measured with a luminometer. The light production is directly proportional to the concentration of TPO antibody in the sample. The amount of analyte in the sample is determined from a stored, multipoint calibration curve. The analyte in the calibrator is traceable to international standard WHO 66/387.(Package insert: Access TPO Antibody, Thyroperoxidase Antibody. Beckman Coulter, Inc; 05/2025)
PDF Report
Indicates whether the report includes an additional document with charts, images or other enriched information
Day(s) Performed
Outlines the days the test is performed. This field reflects the day that the sample must be in the testing laboratory to begin the testing process and includes any specimen preparation and processing time before the test is performed. Some tests are listed as continuously performed, which means that assays are performed multiple times during the day.
Monday through Friday, Sunday
Report Available
The interval of time (receipt of sample at Mayo Clinic Laboratories to results available) taking into account standard setup days and weekends. The first day is the time that it typically takes for a result to be available. The last day is the time it might take, accounting for any necessary repeated testing.
Specimen Retention Time
Outlines the length of time after testing that a specimen is kept in the laboratory before it is discarded
Performing Laboratory Location
Indicates the location of the laboratory that performs the test
Fees :
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Test Classification
Provides information regarding the medical device classification for laboratory test kits and reagents. Tests may be classified as cleared or approved by the US Food and Drug Administration (FDA) and used per manufacturer instructions, or as products that do not undergo full FDA review and approval, and are then labeled as an Analyte Specific Reagent (ASR) product.
This test has been cleared, approved, or is exempt by the US Food and Drug Administration and is used per manufacturer's instructions. Performance characteristics were verified by Mayo Clinic in a manner consistent with CLIA requirements.
CPT Code Information
Provides guidance in determining the appropriate Current Procedural Terminology (CPT) code(s) information for each test or profile. The listed CPT codes reflect Mayo Clinic Laboratories interpretation of CPT coding requirements. It is the responsibility of each laboratory to determine correct CPT codes to use for billing.
CPT codes are provided by the performing laboratory.
CPT codes are provided by the performing laboratory.
86376
LOINC® Information
Provides guidance in determining the Logical Observation Identifiers Names and Codes (LOINC) values for the order and results codes of this test. LOINC values are provided by the performing laboratory.
| Test Id | Test Order Name | Order LOINC Value |
|---|---|---|
| TPO | Thyroperoxidase Ab, S | 8099-4 |
| Result Id | Test Result Name |
Result LOINC Value
Applies only to results expressed in units of measure originally reported by the performing laboratory. These values do not apply to results that are converted to other units of measure.
|
|---|---|---|
| TPO | Thyroperoxidase Ab, S | 8099-4 |