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Anti-TPO
Thyroid
Report in 4Hrs
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No Fasting Required
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Thyroid peroxidase antibody test helps diagnose autoimmune thyroiditis like Hashimoto’s disease.
₹899₹1,150
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Anti TPO Test Information Guide
- Why is it done?
- Detects antibodies against thyroid peroxidase (TPO), an enzyme found in thyroid cells that is essential for thyroid hormone production
- Diagnoses autoimmune thyroid disease, particularly Hashimoto's thyroiditis and Graves' disease
- Evaluates patients presenting with thyroid dysfunction symptoms such as fatigue, weight changes, temperature sensitivity, and mood alterations
- Screens individuals with family history of thyroid or autoimmune disorders
- Monitors progression of autoimmune thyroid disease and effectiveness of treatment
- Typically performed when TSH and free T4 levels are abnormal or thyroid dysfunction is clinically suspected
- Often ordered during pregnancy when thyroid antibodies may indicate increased miscarriage or preterm delivery risk
- Normal Range
- Negative/Normal Result: < 35 IU/mL (or < 35 mIU/L) - Indicates absence of anti-TPO antibodies; most laboratories use this cutoff value
- Borderline/Weakly Positive: 35-100 IU/mL - May indicate early autoimmune thyroid disease or low-level antibody presence; clinical correlation needed
- Positive Result: > 100 IU/mL (highly positive) - Strong evidence of autoimmune thyroid disease
- Units of Measurement: IU/mL (International Units per milliliter) or mIU/L (milli-International Units per liter)
- Note: Reference ranges may vary slightly between laboratories; always consult the specific laboratory's reference range provided with test results
- Normal results do not entirely exclude autoimmune thyroid disease, as some patients have seronegative disease
- Interpretation
- Negative Results (< 35 IU/mL): No detectable anti-TPO antibodies present; low probability of autoimmune thyroid disease, though other thyroid conditions may still exist
- Positive Results (> 35 IU/mL): Presence of anti-TPO antibodies suggests autoimmune thyroid disease; higher titers correlate with greater likelihood of thyroid dysfunction
- High Titers (> 1000 IU/mL): Strong evidence of severe autoimmune thyroid destruction; often associated with active Hashimoto's thyroiditis
- Combined with TSH and Free T4: Anti-TPO results must be interpreted alongside thyroid function tests for complete clinical picture; positive antibodies with normal TSH may indicate subclinical disease
- Factors Affecting Results: Pregnancy (antibodies may fluctuate), recent thyroid surgery, radiation therapy, medications (lithium, interferon), other autoimmune conditions, selenium and iodine deficiency, and stress levels can influence results
- Seronegative Disease: Approximately 10-15% of patients with autoimmune thyroid disease have negative anti-TPO antibodies; clinical symptoms and other antibodies (anti-thyroglobulin) should be considered
- Timing Considerations: Antibody levels may decrease over time with successful treatment; serial testing may be recommended to monitor disease progression or treatment response
- Associated Organs
- Primary Organ Involved: Thyroid gland (endocrine gland in the neck that produces thyroid hormones T3 and T4, essential for metabolism, growth, and energy production)
- Associated Conditions - Hashimoto's Thyroiditis: Most common cause of hypothyroidism in iodine-sufficient regions; leads to progressive thyroid tissue destruction and decreased hormone production
- Associated Conditions - Graves' Disease: Most common cause of hyperthyroidism; anti-TPO antibodies present alongside TSH receptor antibodies; causes excessive thyroid hormone production
- Subclinical Thyroid Disease: Early stage of autoimmune thyroid disease with positive antibodies but normal thyroid function tests; may progress to clinical disease over time
- Postpartum Thyroiditis: Temporary autoimmune thyroid inflammation occurring within first year after delivery; anti-TPO antibodies often elevated; usually resolves but may lead to permanent hypothyroidism
- Other Associated Autoimmune Conditions: Type 1 diabetes mellitus, celiac disease, rheumatoid arthritis, lupus, Sjögren's syndrome, pernicious anemia, and Addison's disease may coexist with autoimmune thyroid disease
- Potential Complications: Untreated hypothyroidism leads to myxedema, cardiovascular disease, infertility, and neurological complications; untreated hyperthyroidism causes thyroid storm, atrial fibrillation, and osteoporosis
- Pregnancy-Related Risks: Elevated anti-TPO antibodies associated with increased miscarriage risk, preterm delivery, and adverse fetal outcomes; may require additional monitoring during pregnancy
- Follow-up Tests
- Thyroid Stimulating Hormone (TSH): Always recommended in conjunction with anti-TPO; primary screening test for thyroid dysfunction; establishes baseline and guides treatment decisions
- Free Thyroxine (Free T4): Measures active circulating T4; if TSH is abnormal, Free T4 confirms thyroid hormone dysfunction status
- Anti-Thyroglobulin Antibodies (Anti-Tg): Complements anti-TPO testing; approximately 50-60% of Hashimoto's patients have both antibodies; helps confirm autoimmune thyroid disease diagnosis
- TSH Receptor Antibodies (TRAb): Indicated if Graves' disease suspected; helps differentiate between types of autoimmune thyroid disease
- Thyroid Ultrasound: May be recommended to evaluate thyroid structure, assess for nodules, or confirm autoimmune changes in thyroid echo pattern
- Free T3: Less commonly ordered; useful in cases of hyperthyroidism or when T4 to T3 conversion is questioned
- Monitoring Frequency: TSH typically monitored every 6-12 weeks initially after starting therapy, then annually once stable; anti-TPO antibodies usually not repeated unless clinical change occurs as they remain relatively constant
- Pregnancy-Specific Follow-up: Positive anti-TPO in pregnancy warrants more frequent TSH monitoring and possible levothyroxine supplementation; repeat testing in first trimester is often recommended
- Complementary Autoimmune Screening: If positive anti-TPO found, consider screening for other autoimmune conditions (celiac serology, tissue transglutaminase antibodies, rheumatoid factor) given increased autoimmune disease association
- Fasting Required?
- Fasting Requirement: No fasting required for anti-TPO test alone
- Blood Collection Considerations: Standard venipuncture (blood draw) performed; serum sample collected in SST (serum separator tube) or red-top tube
- Fasting When Combined with Other Tests: If anti-TPO is ordered with lipid panel or glucose testing, 8-12 hour fast may be required depending on other tests ordered; check specific laboratory instructions
- Medications to Avoid: No medications need to be held for anti-TPO testing; thyroid medications and levothyroxine may be taken as prescribed
- Timing for TSH Testing: For accurate TSH results when combined with anti-TPO, blood draw should be performed in the morning (preferably 6-9 AM) before taking levothyroxine, as absorption peaks within 2-3 hours
- Patient Preparation: Patient should be relaxed for at least 5 minutes before blood draw; wear loose-fitting clothing to facilitate venipuncture; stay hydrated the day before and day of test
- Iodine and Biotin Supplements: High-dose biotin supplements (>5 mg) should be held 24 hours prior to testing as they may interfere with immunoassay results; standard multivitamins are acceptable
- Stress and Illness: Acute stress or acute illness may temporarily affect antibody results; testing should ideally be postponed if patient is acutely ill or experiencing significant emotional stress
How our test process works!
