Thyroid peroxidase (TPO) is an enzyme typically found in the thyroid gland, playing a crucial role in the production of thyroid hormones. A TPO test detects antibodies against TPO in the blood. If someone has a thyroid disorder diagnosis, their doctor may recommend an anti-TPO antibody test and other thyroid screening tests to identify the underlying cause. Pregnant women with autoimmune thyroid conditions may also be advised to undergo a TPO antibody test.

What is an Anti TPO test?

Anti TPO antibodies are detected in the blood through a medical test known as the anti TPO ab test. This test, also referred to as the Thyroid Peroxidase Autoantibody test, measures the levels of thyroid antibodies in the body, which can be indicative of more severe medical conditions. It is particularly useful for individuals with elevated TSH levels, even when their free T4 levels are within the normal range. People may be requested to undergo these tests if they exhibit typical symptoms, including:

• Goitre or an enlarged thyroid gland, characterised by a swollen neck, which is more common in underweight children.
• Muscle deterioration, resulting in a loss of muscle tone.
• Weight gain due to disruptions in metabolism.
• Fatigue, indicating a lack of energy in the body.

The thyroid test anti TPO test serves many purposes, including:

The primary purpose of the anti TPO antibody test is to diagnose and monitor autoimmune thyroid disorders, particularly Hashimoto's thyroiditis and Graves' disease.

• To determine whether the patient has non-autoimmune goitre or an autoimmune thyroid condition.
• To identify hypothyroidism, a condition characterised by reduced thyroxine hormone synthesis.
• To assess the likelihood of recurrence following treatment for Graves' disease.
• To detect idiopathic myxedema, which is characterised by an atrophic (shrunken or reduced in size) thyroid gland and positive autoantibodies against the thyroid gland.
• To ascertain whether a person has previously undergone treatment for thyroid cancer.
• To assess the potential risk to the foetus in pregnant women with thyroid illness.

When should I get this Anti TPO test?

To determine the diagnosis of an autoimmune condition affecting the thyroid, a thyroid antibody test is not usually required. However, physicians may find thyroid antibody testing useful in the following circumstances:

• Hyperthyroidism without an evident reason: In some cases, the presence of an overactive thyroid may indicate Graves’ disease, which can be confirmed through a physical exam and thyroid hormone tests. In less obvious cases, TRAB testing or imaging procedures, such as ultrasound and radionuclide thyroid scans, may aid in diagnosing or ruling out Graves’ Disease.
• Subclinical hypothyroidism: Testing for TPO antibodies can help determine whether a person with high TSH and normal FT4 levels will eventually develop more severe and permanent hypothyroidism or remain subclinical, with no noticeable symptoms.
• Goitre: In cases where the thyroid gland has enlarged abnormally, some medical professionals recommend testing for TPOAb, even if thyroid hormone levels are normal.
• Monitoring following treatment for thyroid cancer: TgAb levels may be checked when someone is undergoing follow-up thyroglobulin testing after therapy, as some thyroglobulin tests may be affected by their presence.

What happens during the Anti TPO test?

The process of obtaining a blood sample involves inserting a needle into a vein located in the upper arm. An elastic band is attached to the upper arm before drawing the sample to increase blood circulation in the veins and facilitate the extraction of the sample. An antiseptic solution is applied to the skin at the point of puncture. The patient is likely to experience a mild sting as the needle penetrates the skin. The duration of the blood draw is usually less than one minute.

Procedure for Anti TPO test

The general guidelines for the Anti-TPO test are as follows:

• To locate the vein, the phlebotomist may ask the patient to make a fist or wrap a band around the arm.
• They will use an antiseptic solution to clean the area from which the blood will be extracted.
• To collect the blood sample needed for analysis, they will use a sterile needle.
• After the blood has been drawn, the sample will be placed in a vial or collecting tube.
• Following the procedure, the phlebotomist will apply a bandage over the punctured area to prevent further bleeding and use a cotton ball to stop any bleeding.

The punctured area may experience some minor discomfort or soreness as a result of the treatment. However, these symptoms should be normal and temporary.

Uses of Anti TPO test

Here are some of the primary uses of the anti-TPO test:

• Diagnosis of Autoimmune Thyroid Disorders: The anti-TPO test is commonly used to diagnose autoimmune thyroid disorders, such as Hashimoto's thyroiditis and Graves' disease.
• Monitoring Thyroid Disorders: The test can also be used to monitor the progression of autoimmune thyroid diseases and the effectiveness of treatment.  
• Risk Assessment: Elevated anti-TPO antibody levels in individuals with normal thyroid function may indicate an increased risk of developing thyroid dysfunction in the future. 
• Evaluation of Infertility: In some cases, anti-TPO antibodies may be associated with infertility in women. Testing for these antibodies can be part of the evaluation for infertility issues, as thyroid dysfunction can affect fertility.
• Pregnancy Management: Pregnant women with a history of thyroid disorders or positive anti-TPO antibodies may be at risk of developing gestational thyroid dysfunction or postpartum thyroiditis. 

How to prepare for the Anti TPO test?

In general, no particular preparation is required for the test. However, a few general criteria must be followed:

Inform the doctor about any prescribed and non-prescribed medications, including Ayurvedic Medicines, since this may alter the TPO Test findings.
In the majority of instances, fasting is not necessary for a TPO test. However, it is recommended to consult a physician if an individual is on a particular dietary regimen.

It is important to avoid any undue stress or anxiety associated with the test, as this can potentially affect the outcome of the test, resulting in an incorrect diagnosis. 

Anti TPO test Results

The normal range for Anti-TPO may significantly vary based on the testing technique, the laboratory conducting the test, and other variables. Typically, Anti-TPO ranges are smaller than 9.0 IU/mL, and anything above this range is considered abnormal.

Conclusion

The TPO antibodies test is just one of several thyroid-related tests, and for an accurate diagnosis and the selection of the best course of action, its interpretation should be carried out in conjunction with other thyroid function tests (such as TSH, T3, and T4) and clinical evaluation.

A team of senior pathologists and technicians offers diagnostic services at CARE Hospitals. We offer a wide range of clinical laboratory tests and profiles used to confirm diagnoses, anticipate early identification, screen for conditions, and/or monitor patients' health.

FAQs

Q1. What is a normal anti-TPO level?

Ans. A normal level of TPO antibody is considered when the amount of antibodies in the body is less than 9 IU/mL. There is no cause for concern in such cases.

Q2. What happens if anti-TPO is high?

Ans. An antibody level exceeding 9 IU/mL is indicative of an autoimmune thyroid disorder, including Hashimoto's disease or Graves' disease, and should be treated accordingly.

Q3. How can I reduce my anti- TPO naturally?

Ans. To reduce anti-TPO levels naturally:

• Allow yourself to unwind.
• Reduce or discontinue the use of NSAIDs that can harm the stomach lining and start an elimination diet.
• Avoid environmental triggers.
• Selenium is one of the essential vitamins that has been shown to be particularly effective in lowering thyroid antibodies.