Comprehensive Thyroid Panel (TSH, Free T3, Free T4, TPO Antibodies)
Complete thyroid evaluation measuring TSH, Free T3, Free T4, and TPO antibodies to assess thyroid function and detect autoimmune thyroid conditions.
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LevelPanel has no business or affiliate relationship with Quest or LabCorp. These links are provided as a public service.
Lab testing services linked from this site are not available to residents of Alaska, Arizona, or Hawaii, unless otherwise noted on the lab's own website.
This publication is not intended to solicit the purchase of laboratory testing from any individual consumer.
What this test measures
This panel evaluates four thyroid markers that together provide a complete view of thyroid hormone production, utilization, and immune status. TSH measures the pituitary gland's regulatory signal to the thyroid. Free T3 and free T4 are the unbound, biologically active forms of the two primary thyroid hormones, reflecting how much active hormone is available to drive metabolism, heart rate, body temperature, and energy regulation. Thyroid peroxidase (TPO) antibodies screen for autoimmune attack on the thyroid gland, the underlying cause of Hashimoto's thyroiditis and a contributing factor in Graves' disease.
The inclusion of TPO antibodies is what distinguishes this panel from basic thyroid testing. In early autoimmune thyroid disease, TPO antibodies can be elevated for months or years before TSH and thyroid hormones begin to shift. Detecting this autoimmune activity early provides an opportunity for closer monitoring and earlier intervention. The panel is particularly valuable for individuals with thyroid symptoms but normal TSH, a family history of thyroid disease, or other autoimmune conditions that increase the likelihood of thyroid involvement.
What's included
Who should consider this test
You might consider this test if you are experiencing any of the following:
- Individuals experiencing unexplained fatigue, weight changes, mood swings, or temperature sensitivity
- Those with a family history of thyroid disease or autoimmune conditions
- Individuals with persistent thyroid symptoms despite normal TSH results from previous testing
- People taking thyroid medication who want to monitor their complete hormone profile and antibody levels
- Those concerned about Hashimoto's thyroiditis or other autoimmune thyroid conditions
- Individuals seeking comprehensive thyroid screening as part of preventive health monitoring
What to expect
Preparation
No fasting is required for this test. Individuals taking thyroid medication should consult with their healthcare provider about timing, as some may recommend testing before taking the morning dose. Biotin supplements should be stopped 72 hours before testing as they can interfere with results.
Sample Type
A simple blood draw from a vein in the arm, similar to any routine blood test.
Collection
The blood sample collection takes just a few minutes at any participating laboratory location. No special procedures or extended appointments are needed.
Turnaround
Results are typically available within 1-2 business days and will be securely delivered through the online patient portal.
Understanding your results
The four markers are most informative when interpreted as a set. Normal results across all four generally indicate healthy thyroid function and no autoimmune activity. Abnormal TSH with corresponding shifts in free T3 or free T4 points toward a specific thyroid disorder, while elevated TPO antibodies in the setting of normal hormones may indicate early autoimmune thyroiditis that has not yet disrupted hormone production. Healthcare providers look for the pattern across all four values, track trends over time, and consider symptoms and clinical history to determine whether treatment or continued monitoring is appropriate.
| Population | Reference Range | Notes |
|---|---|---|
| Adults | TSH: 0.45-4.50 mIU/L | Normal TSH levels indicate appropriate pituitary signaling to the thyroid |
| Adults | Free T3: 2.0-4.4 pg/mL | Free T3 represents the active thyroid hormone available to tissues |
| Adults | Free T4: 0.82-1.77 ng/dL | Free T4 is the storage form that converts to active T3 as needed |
| Adults | TPO Antibodies: 0-34 IU/mL (normal is less than 5.6 IU/mL by some lab standards) | Elevated TPO antibodies indicate autoimmune attack on the thyroid |
Reference ranges shown are general guidelines. Your lab report will include the specific reference range used by the laboratory that processed your sample, which is the authoritative range for interpreting your results.
What does a “Low” result mean?
Low TSH levels may indicate hyperthyroidism, where excess thyroid hormone suppresses TSH production. Low Free T3 or Free T4 levels can be a sign of thyroid hypofunction or hypothyroidism. T3 levels are frequently low in sick or hospitalized patients even without thyroid disease. Low TPO antibodies are generally normal and indicate no autoimmune attack on the thyroid. In rare cases, both low TSH and low T4 levels may indicate a pituitary gland problem rather than a thyroid issue.
What does a “High” result mean?
High TSH levels typically indicate hypothyroidism, meaning the thyroid gland is not producing enough thyroid hormone. Elevated Free T3 or Free T4 levels may suggest hyperthyroidism, where the thyroid is producing excess hormones. High TPO antibodies above 35 IU/mL indicate that the immune system is attacking the thyroid gland, which is the primary marker of Hashimoto's thyroiditis. These elevated antibody levels can be present for years before thyroid hormone levels become abnormal, making early detection possible.
Privacy & confidentiality
All test orders are authorized and results reviewed by an independent, board-certified physician who is not the patient's personal doctor. Your thyroid test results are completely confidential and protected by strict privacy protocols. Results are <u>not reported to your personal doctor</u> unless you specifically request it, and they are <u>not added to your medical records</u> or insurance files. The test and results will <u>not appear on insurance statements</u> or explanation of benefits forms, ensuring complete privacy. Your information is never shared with employers, insurance companies, or government agencies. You maintain full control over your health information and can choose to share results with healthcare providers at your discretion. This private testing allows individuals to monitor their thyroid health proactively and seek appropriate care without any impact on their insurance premiums or medical history. All data is encrypted and stored securely, with access limited only to you through your secure online patient portal.
Frequently asked questions
Related tests
TSH Test (Thyroid Stimulating Hormone)
Basic thyroid screening test that's included in this comprehensive panel
View TestFree T4 Test (Thyroxine)
Individual measurement of the main thyroid hormone included in this panel
View TestVitamin D Test
Vitamin D deficiency is common in those with thyroid disorders and autoimmune conditions
View TestVitamin B12 Test
B12 deficiency can cause symptoms similar to thyroid disorders and is common in autoimmune conditions
View TestRelated conditions
Related articles
The Complete Guide to Thyroid Testing: Which Test Do You Actually Need?
Read ArticleWhat Does a High TSH Mean? (And What to Do Next)
Read ArticleTSH vs Full Thyroid Panel: Is the Cheaper Test Enough?
Read ArticleThe Connection Between Thyroid and Weight: What the Science Says
Read ArticleLast reviewed: April 2026
CPT Code: 84443, 84481, 84439, 86376
This test may not be available in: NY, NJ, RI
This page is for informational purposes only and does not constitute medical advice. Always consult with a healthcare provider regarding any health concerns. LevelPanel does not diagnose, treat, or prescribe.
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LevelPanel has no business or affiliate relationship with Quest or LabCorp. These links are provided as a public service.
Lab testing services linked from this site are not available to residents of Alaska, Arizona, or Hawaii, unless otherwise noted on the lab's own website.
This publication is not intended to solicit the purchase of laboratory testing from any individual consumer.
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