Anti-TPO Antibody Test: Purpose, Normal Range and Price

The Anti-TPO Antibody Test, also known as the Anti-Thyroid Peroxidase Antibody Test, is a blood test that detects the presence of antibodies directed against thyroid peroxidase, an enzyme essential for the synthesis of thyroid hormones. Thyroid peroxidase plays a central role in producing thyroxine (T4) and triiodothyronine (T3), both of which regulate metabolism, energy levels, and overall hormonal balance in the body. When the immune system mistakenly targets thyroid peroxidase, it generates Anti-TPO antibodies, which are considered a hallmark marker of autoimmune thyroid disease. The two most common autoimmune thyroid conditions associated with elevated Anti-TPO levels are Hashimoto's thyroiditis and Graves' disease. In India, thyroid disorders are increasingly prevalent, affecting an estimated 42 million people, with autoimmune causes accounting for a significant proportion of hypothyroid cases, particularly among women of reproductive age. The test is clinically valuable not only for diagnosis but also for predicting the likelihood of thyroid dysfunction in individuals with borderline hormone levels. Elevated Anti-TPO antibodies, even in the presence of normal TSH, can indicate subclinical autoimmune activity and a measurable future risk of overt thyroid disease. The test is performed on a small blood sample drawn from a vein, typically from the forearm, and is completed in under five minutes.

Doctors prescribe an Anti-TPO Antibody test in the following situations: Diagnosing autoimmune thyroid disease in patients presenting with unexplained weight gain, persistent fatigue, cold intolerance, hair loss, and dry skin where elevated Anti-TPO antibodies confirm the presence of Hashimoto's thyroiditis, the most common cause of hypothyroidism in India, and direct the treating physician toward appropriate hormone replacement therapy. Evaluating the underlying cause of an overactive thyroid in patients with hyperthyroid symptoms such as palpitations, heat intolerance, tremors, and unexplained weight loss where elevated Anti-TPO levels alongside other thyroid antibody markers help distinguish Graves' disease from non-autoimmune causes of hyperthyroidism, enabling more targeted and effective treatment planning. Investigating unexplained infertility and recurrent pregnancy loss in women of reproductive age where Anti-TPO antibodies have been linked to impaired implantation, early miscarriage, and adverse obstetric outcomes, and many reproductive endocrinologists now include this test as a standard component of the preconception and infertility workup. Monitoring thyroid autoimmunity during and after pregnancy where thyroid antibody positivity significantly increases the risk of postpartum thyroiditis, a condition affecting up to 10 percent of women in India following delivery, and early identification enables timely surveillance, clinical follow-up, and intervention if thyroid function deteriorates. Assessing thyroid risk in patients with established autoimmune conditions such as Type 1 diabetes, rheumatoid arthritis, Sjogren's syndrome, or systemic lupus erythematosus, where autoimmune diseases frequently co-occur and thyroid autoimmunity is a commonly associated but clinically underdiagnosed comorbidity requiring proactive screening. Screening individuals with a strong family history of thyroid disease or autoimmune conditions where early identification of antibody positivity before the onset of clinical symptoms enables closer surveillance, lifestyle guidance, and timely initiation of treatment when thyroid function eventually declines.

The Anti-TPO Antibody Test measures the concentration of anti-thyroid peroxidase antibodies in the blood, expressed in International Units per millilitre (IU/mL). The generally accepted normal reference range is less than 34 IU/mL, though this may vary slightly depending on the laboratory method and analyser used. There are no clinically significant gender-specific reference ranges, although women are statistically far more likely to test positive and to develop associated thyroid disease. Normal (Below 34 IU/mL) A result below 34 IU/mL is considered negative and indicates that no significant autoimmune activity is directed against the thyroid gland. This is reassuring in individuals being evaluated for thyroid dysfunction, though clinical correlation with TSH and free thyroid hormone levels remains essential for a complete assessment. Mildly Elevated (34 to 100 IU/mL) A borderline or mildly elevated result in this range may indicate early or subclinical autoimmune thyroid activity. While overt thyroid disease may not yet be present, such patients are advised to undergo periodic thyroid function monitoring, as the risk of progression to clinical hypothyroidism is meaningfully increased over time and warrants regular follow-up. Markedly Elevated (Above 100 IU/mL) A markedly elevated result above 100 IU/mL strongly suggests active autoimmune thyroid disease, most commonly Hashimoto's thyroiditis or Graves' disease. Very high titres are associated with a greater degree of thyroid tissue inflammation and a substantially higher likelihood of requiring long-term thyroid hormone replacement therapy or specialist endocrinological management.

No specific fasting requirement is mandated for the Anti-TPO Antibody Test. Unlike lipid profiles or blood glucose tests, food and beverages consumed prior to sample collection do not significantly affect antibody concentrations in the blood. However, it is generally advisable to avoid heavy meals immediately before the draw as a routine precaution. Certain medications may influence thyroid function or immune markers, and it is important to inform your healthcare provider about all drugs currently being taken before the test. These include thyroid hormone replacement medications such as levothyroxine, anti-thyroid drugs like methimazole or carbimazole, corticosteroids, and any immunosuppressive agents. Your doctor will advise whether any temporary discontinuation is necessary prior to testing. There is no strict requirement regarding the time of day for sample collection, as Anti-TPO antibody levels do not follow a significant diurnal variation. However, if you are being tested alongside other thyroid markers such as TSH, Free T3, and Free T4, morning collection is often preferred by clinicians to maintain consistency across multiple test visits and to align with standard thyroid panel protocols. Biotin supplementation, commonly taken for hair and nail health, is known to interfere with immunoassay-based thyroid tests and can produce falsely low or falsely high results. It is recommended to stop biotin supplements at least 48 to 72 hours before the test and to inform your healthcare provider if you are a regular user of high-dose biotin products, as this is a frequently overlooked source of inaccurate thyroid test results. Staying adequately hydrated before the test helps facilitate easier venous access and ensures a smooth blood draw process. There are no additional physical or dietary restrictions specific to this test, making it straightforward to prepare for as part of a broader thyroid health investigation.

If you are booking through the SecondMedic platform the Anti-TPO Antibody test price starts at approximately Rs. 1299. The exact price will be confirmed at the time of booking through SecondMedic. If your doctor has prescribed multiple tests alongside Anti-TPO Antibody, SecondMedic health packages include Anti-TPO Antibody as part of a broader thyroid panel at a significantly lower combined price.

SecondMedic offers convenient home sample collection for the Anti-TPO Antibody test, making it easy to get tested without visiting a diagnostic centre. Home collection is available free of charge for orders above Rs. 300. A trained phlebotomist will visit your preferred address between 7 AM and 10 PM, seven days a week, including Sundays and public holidays. Your blood sample is processed at NABL-accredited partner laboratories, and your report is delivered within 24 hours directly to your WhatsApp and email.