Test Detail
Interpreting Results

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Written by
Dr. Shreya Gupta
BDS, MDS - Oral and Maxillofacial Pathology
Reviewed by
Dr. Ashish Ranjan
MBBS, MD (Pharmacology)
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Anti Thyroperoxidase Antibody

Anti Thyroperoxidase Antibody
You need to provide
This test is for
Male, Female
Test Preparation
  1. No special preparation required


What is Anti-TPO?

Anti thyroperoxidase antibody (TPO) are seen in thyroid diseases. The anti TPO antibody test measures the levels of antibodies directed against thyroid peroxidase, an enzyme found in the thyroid gland. This enzyme plays an important role in the production of thyroid hormones. This test is also known as thyroid peroxidase (TPO) antibody (TPOAb) test, thyroid peroxidase autoantibody test, the antimicrosomal antibody test, and antithyroid microsomal antibody test. The presence of these antibodies would help in diagnosing the reason for low levels of thyroid hormones.

Why is Anti-TPO done?

  • To diagnose autoimmune disorders of thyroid like Hashimoto's thyroiditis (swelling of thyroid gland resulting in decreased thyroid function), Grave's disease (overactive thyroid gland resulting in overproduction of thyroid hormones) or idiopathic myxedema (associated with low levels of thyroid hormones)

  • To differentiate between autoimmune disorders of thyroid from non-autoimmune disorders such as goiter or hypothyroidism.

  • To diagnose chronic thyroiditis

  • To diagnose subclinical hypothyroidism

What does Anti-TPO Measure?

TPO is also known as thyroid peroxidase or iodide peroxidase which is an enzyme mainly expressed in the thyroid gland. The thyroid gland is positioned at the lower part of the neck. TPO is found in the cells of the thyroid follicle where it helps in the production of the thyroid hormones. Its basic function is to oxidize iodide ions to form iodine atoms which assist in the production of thyroxine (T4) or triiodothyronine (T3), the thyroid hormones. TPO is an antigenic determinant of autoantibodies in diseases like autoimmune disorders of the thyroid. These antibodies are called as anti-TPO antibodies (anti-Thyroid peroxidase antibodies) which activates complement and might be associated with dysfunction of thyroid and its pathogenesis. To assess these antibodies, Anti-TPO antibody test is carried out.

Interpreting Anti-TPO results


Positive tests may indicate the following:

  • Hashimoto’s thyroiditis
  • Grave’s disease
  • Idiopathic Myxedema
  • Postpartum thyroiditis
  • Nontoxic Nodular Goiter
  • Thyroid cancer

Answers to Patient Concerns & Frequently Asked Questions (FAQs) about Anti-TPO

Frequently Asked Questions about Anti Thyroperoxidase Antibody

Q. What is Hypothyroidism?
Hypothyroidism, also called underactive thyroid or low thyroid is a condition in which the thyroid gland does not produce enough thyroid hormones. It can be commonly caused by intake of low iodine diet or Hashimoto's thyroiditis (an autoimmune disease). Less common causes include previous treatment with radioactive iodine, injury to the pituitary gland which secretes TSH, intake of certain medicines, previous thyroid surgery, or a lack of a functioning thyroid gland at birth.
Q. How is this test performed?
This test is performed on a blood sample. A syringe with a fine needle is used to withdraw blood from a blood vessel in your arm. The healthcare provider will tie an elastic band around your arm to make the blood vessels swell with blood. This makes it easier to withdraw blood. You may be asked to tightly clench your fist. Once the veins are clearly visible, the area is cleaned with an antiseptic solution and then the needle is inserted into the blood vessel to collect the sample. You will feel a tiny pinprick during the procedure. Blood sample once collected will then be sent to the laboratory.
Q. Is there any risk associated with this test?
There is no risk associated with the test. However, since this test involves a needle prick to withdraw the blood sample, in very rare cases, a patient may experience increased bleeding, hematoma formation (blood collection under the skin), bruising or infection at the site of needle prick.
Q. Is there any special preparation required for the test?
No, there is no special preparation required for the test.
Q. What is Thyroid Peroxidase?
It is an enzyme which is produced by the thyroid gland and it plays an important role in the production of thyroid hormones. Sometimes, antibodies are formed against this enzyme for which Anti TPO antibody test is required.
Q. What is an autoimmune disorder?
An autoimmune disorder is a condition when your body’s immune system starts to attack parts of the body such as joints or skin mistaking it for foreign bodies. Autoantibodies start to release in the body which attacks the healthy cells.
Q. What are the risk factors for autoimmune disorders?
The risk factor includes family history, obesity, smoking, blood pressure medications, cholesterol lowering medications and antibiotics.
Q. What is Hashimoto’s thyroiditis?
It is an autoimmune disease where the body’s immune system attacks the thyroid gland. This condition leads to hypothyroidism in which the thyroid gland starts to produce fewer thyroid hormones. A person having a family history of Hashimoto’s thyroiditis or taking too much iodine or getting exposed to radiation fall under the risk of having Hashimoto’s thyroiditis. The symptoms include weight gain, fatigue, paleness or puffiness of the face, joint and muscle pain, constipation, joint and muscle pain, thinning or loss of hair, slowed heart rate, depression, irregular or heavy menstrual periods.
Q. What is subclinical hypothyroidism?
It is an early form of hypothyroidism in which sufficient thyroid hormones are not produced by the thyroid gland. It can be seen in persons who have a family history of autoimmune disorders of thyroid or injury to thyroid or use of radioactive iodine therapy or with the use of medications containing iodine or lithium. The symptoms include fatigue, depression, constipation, weight gain, goiter, hair loss, intolerance to cold.
Q. What additional tests can be performed in case the Anti TPO test results are not in the normal range?
If the Anti TPO test results are not in the normal range, your doctor may ask for the following tests: Thyroid Hormone Binding Globulin (TBG) Thyroid profile
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Clinitech Laboratory Private Limited was registered at Registrar of Companies Mumbai on 19 March, 2010 and is categorised as Company limited by Shares and an Non-govt company. Clinitech Laboratory Private Limited's Corporate Identification Number (CIN) is U85195MH2010PTC201078 and Registeration Number is 201078. Clinitech Laboratory Private Limited registered address on file is AL - 1 / 545 & 546, SECTOR 16, AIROLI, NAVI MUMBAI MH 400708 IN, Navi Mumbai - 400708, Maharashtra, India. Clinitech...
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Virendra Jadhav
Booked test for mother who is about to undergo cataract ssurgery.Phlebo guys managed well in heavy rains.Report same day

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