Complete Thyroid Panel
The Complete Thyroid Panel measures six biomarkers — TSH, Free T3, Free T4, Reverse T3, TPO Antibodies, and TG Antibodies — providing the most comprehensive single-draw assessment of thyroid function, hormone conversion adequacy, and autoimmune thyroid disease status available to practitioners.
6
Biomarkers
Blood (serum)
Sample
5–7 business days
Turnaround
No
Fasting
What is the Complete Thyroid Panel test?
The Complete Thyroid Panel is the most comprehensive single-draw thyroid assessment available. It measures six key biomarkers that together provide a complete picture of thyroid function, hormone conversion adequacy, and autoimmune thyroid disease status. Standard TSH testing alone misses a significant proportion of thyroid pathology. Patients with normal TSH but abnormal Free T3, elevated Reverse T3, or elevated thyroid antibodies represent a clinically important population that standard screening fails to identify. The Complete Thyroid Panel closes this diagnostic gap in a single, cost-effective blood draw.
What does the Complete Thyroid Panel test measure?
Primary pituitary thyroid signal. First-line indicator of thyroid dysfunction.
Elevated in hypothyroidism, suppressed in hyperthyroidism.
The active thyroid hormone at cellular level. Produced primarily by peripheral conversion of T4 to T3 via deiodinase enzymes.
Assesses T4-to-T3 conversion adequacy. Essential for patients on levothyroxine who remain symptomatic with normal TSH and Free T4.
The unbound, biologically available fraction of thyroxine. Primary thyroid hormone produced directly by the thyroid gland.
Confirms hypothyroidism or hyperthyroidism following abnormal TSH. Guides levothyroxine dosing.
Inactive T4 metabolite produced when the body shunts T4 away from active T3 production. Elevated in chronic illness, stress, and impaired conversion states.
Elevated RT3 suggests impaired T4-to-T3 conversion — commonly seen in chronic fatigue, adrenal dysfunction, iron deficiency, and critical illness.
Autoantibodies targeting thyroid peroxidase, the enzyme responsible for thyroid hormone synthesis. Primary serological marker for autoimmune thyroid disease.
Positive in >90% of Hashimoto's thyroiditis and ~75% of Graves disease. Confirms autoimmune aetiology of thyroid dysfunction.
Autoantibodies targeting thyroglobulin, the precursor protein for thyroid hormones. Secondary autoimmune thyroid marker.
Positive in ~60% of Hashimoto's. Particularly useful when TPO antibodies are negative but autoimmune thyroid disease is still suspected.
Why is the Complete Thyroid Panel test ordered?
- Suspected Hashimoto's thyroiditis or autoimmune thyroid disease
- Suspected Graves disease
- Unexplained fatigue, weight gain, or brain fog with normal TSH
- Monitoring levothyroxine therapy with persistent symptoms despite normal TSH
- Pre-conception comprehensive thyroid screening
- Abnormal TSH requiring full panel follow-up
- Co-existing autoimmune conditions suggesting thyroid autoimmunity
- Family history of thyroid disease
Sample collection and turnaround
Sample type
Blood (serum)
Fasting required
No
Collection method
Venipuncture at patient service centre
Turnaround
5–7 business days
Collection notes
If patient is on levothyroxine, draw blood before the morning dose.
What can affect Complete Thyroid Panel results?
High-dose biotin can interfere with multiple assays in the panel. Discontinue 48–72 hours before testing.
Taking levothyroxine before the blood draw can transiently elevate Free T4. Draw blood before the morning dose.
What do Complete Thyroid Panel results mean?
Elevated
Elevated TSH with low Free T4 confirms primary hypothyroidism. Elevated antibodies (TPO/TG Ab) confirm autoimmune aetiology. Elevated Reverse T3 with normal TSH suggests impaired conversion.
Normal
All markers within range confirms euthyroid status. Isolated elevated antibodies with normal function markers indicates autoimmune thyroid disease in preclinical phase — monitor annually.
Reduced
Suppressed TSH with elevated Free T4 and/or Free T3 confirms hyperthyroidism. Low TSH with low Free T4 suggests central hypothyroidism.
Note: Interpret all six markers together as a panel, not individually. The clinical picture emerges from the pattern of results, not from any single value.
Frequently asked questions
The Complete Thyroid Panel measures six biomarkers: TSH, Free T3, Free T4, Reverse T3, TPO Antibodies, and TG Antibodies. Together they assess thyroid function, T4-to-T3 conversion, and autoimmune thyroid disease status.
How to access the Complete Thyroid Panel test
The Complete Thyroid Panel reference page is free and open to all practitioners. Create a free practitioner account to see pricing, save tests to your list, and generate requisition forms. Verification takes 1–2 business days.
Create Free AccountAbout this page
Published: January 15, 2025
Last reviewed: January 15, 2025
- Garber JR, et al. Clinical practice guidelines for hypothyroidism in adults. (2012)
- Ross DS, et al. 2016 ATA Guidelines for Diagnosis and Management of Hyperthyroidism. (2016)
This content is for licensed healthcare practitioners only and does not constitute medical advice. Clinical decisions should be based on the full clinical picture and not on any single test result.
Related tests
thyroid endocrine
TSH
The TSH test measures Thyroid Stimulating Hormone produced by the anterior pituitary gland. It is the recommended first-line screening test for thyroid dysfunction, with elevated TSH indicating primary hypothyroidism and suppressed TSH indicating hyperthyroidism. TSH alone does not assess T4-to-T3 conversion or exclude central hypothyroidism.
thyroid endocrine
Total T4
The Total T4 test measures total thyroxine (bound and unbound fractions) in serum. It is specifically indicated for neonatal thyroid screening, pregnancy monitoring under specialist protocol, investigation of TBG-related binding abnormalities, and confirmation of suspected Free T4 immunoassay interference. In routine practice, Free T4 has replaced Total T4 as the standard of care.