Lab Dept:


Test Name:


General Information

Lab Order Codes:



Antithyroid Antibodies; Hashimoto Disease; Microsomal Antibodies; Thyroid Antibody Group; Thyroid Microsomal Antibodies; Thyroid Peroxidase; TPO Antibodies

CPT Codes:

86376 - Microsomal antibodies

Test Includes:

Thyroperoxidase antibody level reported in IU/mL.


Test Indications:

As an aid in the diagnosis of thyroid autoimmune disorders. Differentiating thyroid autoimmune disorders from non-autoimmune goiter or hypothyroidism. As a diagnostic tool in deciding whether to treat a patient who has subclinical hypothyroidism. See Mayo's Thyroid Function Algorithm for more information.

Lab Testing Sections:

Serology - Sendouts

Referred to:

Mayo Medical Laboratories (MML Test: TPO)

Phone Numbers:

MIN Lab: 612-813-6280

STP Lab: 651-220-6550

Test Availability:

Daily, 24 hours

Turnaround Time:

1 - 3 days, test performed Monday - Saturday

Special Instructions:

See Patient Preparation. Obtain Red NO GEL tube from the lab.


Specimen Type:



Red top (NO GEL) tube

Draw Volume:

1.8 mL (Minimum: 1.5 mL) blood

Processed Volume:

0.6 mL (Minimum: 0.5 mL) serum


Routine venipuncture

Special Processing:

Lab Staff: Centrifuge specimen within 2 hours of collection, remove serum aliquot into a plastic screw-capped round bottom vial. Ship and store at refrigerated temperatures. Forward promptly.

Patient Preparation:

Twelve hours before this blood test, do no take multivitamins or dietary supplements containing biotin or vitamin B7.

Sample Rejection:

Gross hemolysis; mislabeled or unlabeled specimens; specimens in gel tubes


Reference Range:

<9.0 IU/mL

Note: Reference values apply to all ages

Critical Values:



Moderately increased levels of TPO antibodies may be found in patients with non-thyroid autoimmune disease such as pernicious anemia, type 1 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.


Chemiluminometric Immunoassay


Mayo Medical Laboratories April 2016