Quick Facts
- Sample: Blood draw (serum)
- Fasting: No fasting required
- Turn-around: 4–6 business days. May take longer based on weather, holiday, or lab delays.
Benefits
- Comprehensive thyroid assessment beyond standard TSH and T4 tests
- Early autoimmune detection identifies Hashimoto's and Graves' disease
- Reverse T3 insights reveal hormone conversion problems causing symptoms
- No doctor referral needed for convenient, private testing
Who Is This Test For?
- Individuals experiencing unexplained fatigue, weight changes, or mood swings
- People with family history of thyroid or autoimmune diseases
- Those with persistent symptoms despite normal thyroid hormone levels
- Patients monitoring existing autoimmune thyroid conditions
- Anyone seeking comprehensive thyroid health evaluation
- Individuals with chronic stress or illness affecting thyroid function
How It Works – Just 3 Steps
- Order online or visit a walk-in lab location near you
- Provide blood sample via quick venipuncture at the lab
- Receive results within 4-6 business days
FAQ
What does this test measure? TPO and thyroglobulin antibodies, and Reverse T3 to assess autoimmune thyroid disease and hormone metabolism.
Do I need to fast before this test? No fasting required. Best tested in the morning when hormone levels are most stable.
Can this detect hypothyroidism and hyperthyroidism? Yes, when combined with TSH and thyroid hormone measurements, it helps diagnose both conditions and their autoimmune causes.
What if my antibodies are elevated? Elevated thyroid antibodies suggest autoimmune thyroid disease requiring medical evaluation and potential treatment.
How accurate are thyroid antibody tests? Thyroid antibody tests exceed 90% sensitivity and specificity, making them highly reliable diagnostic tools.
Should I stop thyroid medication before testing? Consult your healthcare provider about medication timing, as some may need adjustment before testing.
More Details
What is the purpose of this test?
This comprehensive panel evaluates thyroid function and detects autoimmune thyroid disorders by measuring specific antibodies that attack the thyroid gland. The test identifies conditions like Hashimoto's thyroiditis and Graves' disease, which affect 5-10% of the U.S. population (American Thyroid Association 2023).
Additionally, it measures Reverse T3 (rT3), an inactive form of thyroid hormone that helps assess how effectively your body converts T4 into active T3. High Reverse T3 levels may indicate nonthyroidal illness syndrome, chronic stress, or inflammation that can cause hypothyroid symptoms even when standard thyroid tests appear normal.
Who would benefit from this test?
This test is particularly valuable for health-conscious individuals seeking detailed thyroid evaluation beyond routine screening. It's ideal for those with persistent symptoms like fatigue, weight changes, or mood disorders when standard thyroid tests are inconclusive.
People with family history of thyroid or autoimmune diseases, those monitoring known thyroid conditions, and individuals experiencing symptoms suggestive of thyroid imbalance would benefit significantly. The test is also useful for assessing nonthyroidal illness syndrome in those with chronic illness or stress.
When should I order this test?
Consider ordering when experiencing symptoms like unexplained fatigue, weight changes, hair loss, mood disturbances, or temperature sensitivity. It's particularly important when you have a family history of thyroid disease or other autoimmune conditions.
The test is also valuable for monitoring existing autoimmune thyroid conditions, evaluating treatment effectiveness, or when standard thyroid tests don't explain persistent symptoms. Early morning testing provides the most stable hormone levels for accurate results.
How do I interpret the results?
TPO Antibodies
- Normal Range: <35 IU/mL
- Elevated Levels May Indicate: Hashimoto's thyroiditis, autoimmune thyroid disease
Thyroglobulin Antibodies
- Normal Range: <20 IU/mL
- Elevated Levels May Indicate: Autoimmune thyroiditis, thyroid cancer monitoring
Reverse T3
- Normal Range: 8–25 ng/dL
- Elevated Levels May Indicate: Nonthyroidal illness, impaired T4 to T3 conversion
Reverse T3 levels are elevated in up to 70% of critically ill patients, reflecting the body's protective response to stress or illness (LabCorp 2023).
Disclaimer: Reference ranges may vary by laboratory. Listed ranges are general guidelines and may differ from those used by the performing lab. Always consult your healthcare provider for interpretation.
Pre-test preparation
No fasting is required for this test, making it convenient for scheduling. However, inform the lab about any thyroid medications you're taking, as some may need to be paused based on physician advice.
For optimal results, schedule testing in the morning when hormone levels are most stable. Avoid biotin supplements for 72 hours before testing, as they can interfere with certain assays. Stay well-hydrated and maintain your normal routine leading up to the test.
How often should I get tested?
- Monitoring autoimmune thyroid disease: Every 6-12 months
- After starting thyroid treatment: Every 6-8 weeks initially
- Stable thyroid condition: Annually
- Family history of thyroid disease: Every 2-3 years
- Symptoms of thyroid dysfunction: As needed for evaluation
Why early detection matters
Early identification of thyroid antibodies can prevent progression to overt hypothyroidism, reducing healthcare costs and improving quality of life (Mayo Clinic 2024). Detecting autoimmune thyroid disease before significant thyroid damage occurs allows for earlier intervention and better treatment outcomes.
Untreated autoimmune thyroid conditions can lead to complications including cardiovascular disease, osteoporosis, and mental health issues. Early detection enables proactive management strategies, lifestyle modifications, and appropriate medical treatment to maintain optimal thyroid function and overall health.
Related tests you may consider
Thyroid Stimulating Hormone (TSH) - Primary screening test that complements antibody testing for comprehensive thyroid evaluation.
Free T4 and Free T3 - Measures active thyroid hormones to assess thyroid gland output and peripheral hormone conversion.
Thyroid Stimulating Immunoglobulin (TSI) - Useful for diagnosing Graves' disease when hyperthyroidism is suspected.
