Essential Thyroid Profile — Foundational Thyroid Function Test (fT3, fT4, TPOab & TSH)
The Essential Thyroid Profile provides a comprehensive analysis of the four most critical thyroid function markers: free T3 (fT3), free T4 (fT4), thyroid peroxidase antibodies (TPOab), and thyroid-stimulating hormone (TSH). This essential blood test goes beyond the standard TSH-only test to give you — and your practitioner — a complete and actionable picture of thyroid function and autoimmune activity.
What's Measured

TSH — the standard pituitary signal for thyroid activity
Free T4 (fT4) — the inactive thyroid hormone that serves as a precursor to T3
Free T3 (fT3) — the active thyroid hormone that drives metabolism, energy, and mood
TPO Antibodies (TPOab) — detects the autoimmune attack on the thyroid gland associated with Hashimoto's thyroiditis

Who Needs the Essential Thyroid Profile?
This profile is ideal for anyone experiencing unexplained fatigue, weight changes, cold intolerance, hair thinning, brain fog, depression, constipation, dry skin, or other symptoms of thyroid dysfunction. It is especially valuable for identifying Hashimoto's thyroiditis — the most common cause of hypothyroidism — which TSH alone will not diagnose. Results reviewed by Michelle Tonkin ND.
Frequently Asked Questions
Q: Why isn't TSH alone enough?
A: TSH measures the pituitary's signal to the thyroid but doesn't tell you how much active hormone (T3) is actually in your cells. Many people with normal TSH still have low fT3 and Hashimoto's antibodies, leading to untreated symptoms.
Q: What does a positive TPO antibody test mean?
A: A positive TPO result indicates your immune system is attacking your thyroid gland — a hallmark of Hashimoto's thyroiditis. Early detection allows for dietary and lifestyle interventions to slow the autoimmune process.
Q: Will I receive recommendations with my results?
A: Yes — results include a practitioner review and personalized natural health recommendations from Michelle Tonkin ND.