Thyroid Peroxidase Antibodies (TPO)

The Thyroid Peroxidase Antibodies (TPO) test contains 1 test with 1 biomarker.

Brief Description: The Thyroid Peroxidase Antibodies (TPOAb) test is a laboratory test that measures the presence and level of antibodies against thyroid peroxidase in the blood. Thyroid peroxidase is an enzyme found in the thyroid gland, which plays a crucial role in the production of thyroid hormones.

This test is Qualitative once TPO Antibody levels reach 900 IU/mL. For patients who are suspected to have results greater than 900 IU/mL, order TPO Antibody Endpoint #15116.

Also Known As: Thyroid Autoantibodies Test, Antithyroid Antibodies Test, Thyroid Peroxidase Antibody Test, Thyroperoxidase Antibody Test, TPO Test, Anti-TPO Test

Collection Method: Blood Draw

Specimen Type: Serum

Test Preparation: No preparation required

When is a Thyroid Peroxidase test ordered?

A Thyroid Peroxidase Antibodies test may be ordered in the following situations:

  1. Thyroid Disorders Evaluation: It is commonly ordered to assess the presence of autoimmunity in thyroid disorders such as Hashimoto's thyroiditis and Graves' disease. These conditions involve abnormal immune responses against the thyroid gland, resulting in either hypothyroidism (Hashimoto's) or hyperthyroidism (Graves').

  2. Unexplained Symptoms: If a person presents with symptoms suggestive of thyroid dysfunction, such as fatigue, weight changes, hair loss, or changes in heart rate, the test may be ordered to investigate autoimmune thyroid conditions.

  3. Monitoring Autoimmune Thyroiditis: For individuals already diagnosed with autoimmune thyroiditis, the test helps monitor disease progression and treatment efficacy.

What does a Thyroid Peroxidase blood test check for?

Thyroid Peroxidase is a thyroid antibody. Thyroid autoantibodies are antibodies that form when a person's immune system incorrectly attacks thyroid gland or thyroid protein components, causing chronic thyroid inflammation, tissue destruction, and/or thyroid function disruption. Specific thyroid autoantibodies in the blood are detected and quantified using laboratory techniques.

The thyroid gland is a tiny, butterfly-shaped gland in the throat that rests flat against the windpipe. Thyroxine and triiodothyronine, the two key hormones it generates, are critical in regulating the pace at which the body uses energy. Thyroid stimulating hormone stimulates the thyroid to generate T4 and T3 as needed by the body's feedback system. This mechanism aids in the maintenance of a reasonably constant level of thyroid hormones in the blood. Thyroid antibodies can cause chronic diseases and autoimmune disorders linked with hypothyroidism or hyperthyroidism, such as Graves disease or Hashimoto thyroiditis, when they interfere with this process.

Lab tests often ordered with a Thyroid Peroxidase test:

When a TPOAb test is ordered, it's typically part of a broader assessment of thyroid function and autoimmune activity. Several other tests are commonly ordered alongside it:

  1. Thyroid-Stimulating Hormone (TSH):

    • Purpose: TSH is a hormone produced by the pituitary gland that regulates the production of thyroid hormones. It's the primary screening test for thyroid dysfunction.
    • Why Is It Ordered: To assess overall thyroid gland activity. In autoimmune thyroid disease, TSH levels can be elevated (indicating hypothyroidism) or suppressed (indicating hyperthyroidism).
  2. Free T4 (Thyroxine) and Free T3 (Triiodothyronine):

    • Purpose: To measure the levels of active thyroid hormones in the blood.
    • Why Is It Ordered: To assess the thyroid gland's ability to produce thyroid hormones. In Hashimoto's thyroiditis, levels may be low, whereas, in Graves' disease, they might be high.
  3. Thyroglobulin Antibodies (TgAb):

    • Purpose: To detect antibodies against thyroglobulin, another thyroid-specific protein.
    • Why Is It Ordered: Like TPOAb, TgAb can indicate autoimmune thyroid disease and is often elevated in Hashimoto's thyroiditis and Graves' disease.
  4. Complete Blood Count (CBC):

    • Purpose: To provide a general overview of health and detect conditions like anemia.
    • Why Is It Ordered: Thyroid disorders can affect blood cell production, and a CBC can help identify such effects.
  5. Vitamin D Levels:

    • Purpose: To measure the level of Vitamin D, which can be low in autoimmune diseases.
    • Why Is It Ordered: To assess for Vitamin D deficiency, which is common in individuals with autoimmune thyroid diseases.
  6. Thyroid-Stimulating Immunoglobulin (TSI) or TSH Receptor Antibody (TRAb):

    • Purpose: To detect antibodies that stimulate the thyroid, often associated with Graves' disease.
    • Why Is It Ordered: These tests can help confirm a diagnosis of Graves' disease, where the immune system produces antibodies that over-stimulate the thyroid.
  7. Anti-Nuclear Antibodies (ANA):

    • Purpose: To screen for other autoimmune disorders.
    • Why Is It Ordered: People with one autoimmune disorder, like autoimmune thyroid disease, are at increased risk for other autoimmune conditions.

These tests, along with the TPOAb test, provide a comprehensive view of thyroid function, the presence and impact of autoimmune processes, and overall health status. They are crucial in diagnosing, monitoring, and managing autoimmune thyroid diseases. The specific tests chosen will depend on the individual’s symptoms, medical history, and the results of the initial tests.

Conditions where a Thyroid Peroxidase test is recommended:

The Thyroid Peroxidase Antibodies test is commonly ordered for the following conditions or diseases:

  1. Hashimoto's Thyroiditis: This autoimmune condition leads to chronic inflammation and destruction of the thyroid gland, resulting in hypothyroidism.

  2. Graves' Disease: In Graves' disease, the immune system produces antibodies that stimulate the thyroid gland, causing excessive production of thyroid hormones and hyperthyroidism.

How does my healthcare provider use a Thyroid Peroxidase test?

Healthcare providers use the results of the Thyroid Peroxidase Antibodies test to:

  1. Confirm Autoimmune Thyroiditis: Elevated levels of thyroid peroxidase antibodies confirm the presence of autoimmune thyroiditis and help guide appropriate treatment strategies.

  2. Predict Risk: Elevated antibody levels in individuals with normal thyroid function can indicate an increased risk of developing thyroid dysfunction in the future. This information aids in monitoring and preventive interventions.

  3. Monitoring Autoimmune Thyroiditis: For individuals already diagnosed with autoimmune thyroiditis, the test helps assess the progression of the disease and response to treatment.

It is important to note that the interpretation of Thyroid Peroxidase Antibodies test results should be done by qualified healthcare professionals in the context of the patient's medical history, symptoms, and other laboratory findings.

What do my thyroid antibody results mean?

Negative test results show that thyroid autoantibodies were not detected in the blood at the time of testing, implying that symptoms are caused by anything other than autoimmune disease. However, autoantibodies are absent in a small number of persons with autoimmune thyroid disease. Repeat testing may be done at a later date if it is suspected that the autoantibodies will develop over time, as with several autoimmune illnesses.

Thyroid antibodies can be identified in a range of thyroid and autoimmune conditions, including thyroid cancer, type 1 diabetes, rheumatoid arthritis, pernicious anemia, and autoimmune collagen vascular diseases, with mild to moderately high levels.

Thyroid autoimmune disorders such as Hashimoto thyroiditis and Graves disease are usually associated with significantly elevated amounts.

Thyroid antibodies, in general, indicate the presence of an autoimmune thyroid illness, and the higher the level, the more likely it is. Autoantibody levels that grow over time may be more relevant than steady levels because they may suggest an increase in the severity of autoimmune illness. All of these antibodies can increase the risk of hypothyroidism or hyperthyroidism in a growing baby or infant if they are present in a pregnant mother.

If a person with thyroid cancer has thyroglobulin antibodies, the testing for thyroglobulin levels may be hampered. This could suggest that the thyroglobulin test can't be utilized as a tumor marker or to track a person's thyroid cancer progression. The presence of thyroglobulin antibodies has little effect on some testing procedures, including mass spectrometry. The thyroglobulin test can be utilized as a tumor marker when tested in these methods, regardless of whether or not thyroglobulin antibodies are present. If a method is utilized that is impacted by thyroglobulin antibodies, the antibodies' levels can be used as a tumor marker to monitor thyroid cancer. If they first remain high or fall low but then rise over time, the treatment was ineffective and the malignancy is likely to continue or recur. If the levels are dropping and/or have dropped to low or undetectable levels, the therapy is more likely to have been successful in eradicating the malignancy.

Thyroid antibodies can be found in a small percentage of patients who are otherwise healthy. The incidence of these antibodies is higher in women, increases with age, and implies an increased risk of developing thyroid illness in the future for thyroid peroxidase antibodies. If a person has a thyroid antibody but no obvious thyroid disease, the healthcare professional will monitor the person's health over time. While the majority of people will never have thyroid problems, a small percentage will.

Most Common Questions About the Thyroid Peroxidase Antibodies test:

Understanding the Test

What is a Thyroid Peroxidase Antibodies test?

The TPO Ab test measures the level of thyroid peroxidase antibodies in your blood. These antibodies are produced by the body's immune system when it mistakenly targets and attacks thyroid peroxidase, an enzyme found in the thyroid gland.

Why would I need a Thyroid Peroxidase Antibodies test?

The TPO Ab test is typically ordered when you have symptoms of a thyroid disorder, or if other thyroid tests such as TSH, free T3, or free T4 suggest thyroid dysfunction. It's commonly used to help diagnose conditions like Hashimoto's thyroiditis or Graves' disease, which are autoimmune conditions.

Interpreting the Results

What do normal results on a Thyroid Peroxidase Antibodies test look like?

Normal results usually indicate that the amount of TPO antibodies in your blood is within the expected range, suggesting that your immune system isn't attacking your thyroid gland. However, exact normal ranges may vary between different laboratories.

What could high levels of Thyroid Peroxidase Antibodies in the test results mean?

High levels of TPO antibodies may suggest an autoimmune thyroid disorder such as Hashimoto's thyroiditis or Graves' disease. These conditions involve the immune system mistakenly attacking the thyroid gland.

Understanding the Implications

What is the role of Thyroid Peroxidase in the body?

Thyroid peroxidase plays a crucial role in the production of thyroid hormones. These hormones regulate many body functions, including metabolism, growth, and development.

What are the symptoms of having high Thyroid Peroxidase Antibodies?

High TPO antibodies themselves don't cause symptoms, but the thyroid disease they may indicate can cause various symptoms. These may include fatigue, weight changes, depression, anxiety, hair loss, feeling too cold or too hot, and many others, depending on whether the thyroid is underactive or overactive.

Dealing with Abnormal Results

What are the next steps if my Thyroid Peroxidase Antibodies test results are high?

If your TPO antibodies are high, your healthcare provider may diagnose you with an autoimmune thyroid disorder. The specific treatment will depend on the exact disorder and your individual symptoms.

Discussion with Healthcare Provider

What should I discuss with my healthcare provider after receiving the results of my Thyroid Peroxidase Antibodies test?

You should discuss the implications of your results, potential underlying conditions, any necessary further tests, and potential treatment options.

Relationship with Other Tests

How does the Thyroid Peroxidase Antibodies test relate to other thyroid tests?

The TPO Ab test is often used in combination with other thyroid tests like TSH, free T3, and free T4 to provide a comprehensive view of thyroid health. If these hormones are out of balance and TPO antibodies are high, it could indicate an autoimmune thyroid disease.

Understanding the Test Components

Why does the Thyroid Peroxidase Antibodies test focus on antibodies?

The presence of TPO antibodies indicates that your immune system is mistakenly attacking your thyroid gland, which can lead to thyroid dysfunction. By measuring these antibodies, we can potentially identify autoimmune thyroid diseases.

Beyond the Test

Can the Thyroid Peroxidase Antibodies test be used to monitor the progression of a thyroid disorder?

Yes, the TPO Ab test can be used to monitor the progression of autoimmune thyroid diseases. If antibody levels decrease with treatment, it suggests that the therapy is effective in reducing the immune system's attack on the thyroid gland.

Comparison with Other Tests

What is the difference between the Thyroid Peroxidase Antibodies test and the Thyroglobulin Antibodies test?

Both tests measure antibodies that target components of the thyroid gland, but they target different proteins. The Thyroid Peroxidase Antibodies test measures antibodies against thyroid peroxidase, an enzyme involved in thyroid hormone production. The Thyroglobulin Antibodies test measures antibodies against thyroglobulin, a protein involved in the storage of thyroid hormones.

Potential Next Steps

What other tests might be ordered if my Thyroid Peroxidase Antibodies test results are abnormal?

If your TPO Ab test is abnormal, other tests might be ordered to evaluate your thyroid function further. These may include a TSH test, Free T3 test, Free T4 test, or a thyroglobulin test.

Additional Information

Can a person with normal thyroid function have elevated Thyroid Peroxidase Antibodies?

Yes, some people may have elevated TPO antibodies but normal thyroid function tests. This could suggest a potential risk for developing thyroid disease in the future, and these individuals may need to be monitored more closely over time.

Role in Health Management

How often should I have a Thyroid Peroxidase Antibodies test?

The frequency of testing would depend on your individual circumstances, including your symptoms and whether you've been diagnosed with a thyroid disorder.

Specific Populations

Can the Thyroid Peroxidase Antibodies test be used in pregnant women?

Yes, it can. Testing for TPO antibodies can be particularly important in early pregnancy as untreated hypothyroidism can lead to complications for both mother and baby.

Is the Thyroid Peroxidase Antibodies test recommended for people with a family history of thyroid disease?

Yes, if you have a family history of thyroid disease, particularly autoimmune thyroid disorders, your healthcare provider may recommend a TPO Ab test among others.

Underlying Conditions

What are the most common diseases associated with high levels of Thyroid Peroxidase Antibodies?

The most common diseases associated with high levels of TPO antibodies are Hashimoto's thyroiditis and Graves' disease, both of which are autoimmune thyroid disorders.

Understanding Test Indications

How does the Thyroid Peroxidase Antibodies test contribute to the diagnosis of Graves' disease?

In Graves' disease, the immune system produces antibodies including TPO Ab that stimulate the thyroid gland to produce excessive amounts of thyroid hormone, leading to hyperthyroidism. The presence of TPO antibodies along with clinical symptoms can aid in the diagnosis of Graves' disease.

What role does the Thyroid Peroxidase Antibodies test play in the diagnosis of Hashimoto's thyroiditis?

In Hashimoto's thyroiditis, the immune system produces antibodies, including TPO antibodies, which attack and damage the thyroid gland leading to underproduction of thyroid hormone (hypothyroidism). Elevated TPO Ab levels are often seen in this condition.

Understanding the Role of Immune System

Why does the body produce Thyroid Peroxidase Antibodies?

The body produces TPO antibodies when the immune system mistakenly identifies thyroid peroxidase as a threat. This can lead to inflammation and damage to the thyroid gland.

Health Impact

What long-term health issues can be caused by high levels of Thyroid Peroxidase Antibodies?

High levels of TPO antibodies can indicate an ongoing immune attack on the thyroid, potentially leading to chronic thyroid disorders such as Hashimoto's thyroiditis or Graves' disease. These conditions can have various long-term effects on health, from heart problems to mental health issues, if not properly managed.

Prevention and Risk Management

Can lifestyle changes influence the levels of Thyroid Peroxidase Antibodies in the body?

While lifestyle factors can't directly affect the level of TPO antibodies, a healthy lifestyle including a balanced diet, regular exercise, and stress management can support overall immune health and may contribute to the management of autoimmune thyroid disorders.

Further Research

What is currently being studied about Thyroid Peroxidase Antibodies?

Research is ongoing to better understand the role of TPO antibodies in autoimmune thyroid diseases, including potential therapeutic approaches to modulate the immune response and lower antibody levels.

Are there promising future treatments related to Thyroid Peroxidase Antibodies?

Scientists are exploring a variety of approaches to treat autoimmune thyroid disorders, including immune-modulating therapies. These therapies aim to reduce the immune system's attack on the thyroid gland and lower TPO antibody levels. However, these treatments are still in the research phase and are not yet available for routine clinical use.

We advise having your results reviewed by a licensed medical healthcare professional for proper interpretation of your results.

The following is a list of what is included in the item above. Click the test(s) below to view what biomarkers are measured along with an explanation of what the biomarker is measuring.

Also known as: Anti-Thyroid Microsomal Antibody, Anti-TPO, Thyroid Peroxidase Antibodies TPO, TPO

Thyroid Peroxidase

*Process times are an estimate and are not guaranteed. The lab may need additional time due to weather, holidays, confirmation/repeat testing, or equipment maintenance.

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