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Individual Labs/Thyroid Function

Quest / Thyroid Function

T3 Reverse, LC/MS/MS

### A Reverse T3 (rT3), Serum lab test measures the level of reverse triiodothyronine in the blood. Reverse T3 is an inactive form of the thyroid hormone triiodothyronine (T3) that is produced when the body converts thyroxine (T4) into rT3...

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What this lab measures

### A Reverse T3 (rT3), Serum lab test measures the level of reverse triiodothyronine in the blood. Reverse T3 is an inactive form of the thyroid hormone triiodothyronine (T3) that is produced when the body converts thyroxine (T4) into rT3...

One individual marker · Quest · Clinician reviewed

How testing works

  1. Order online

    Choose your marker and add a brief medical history so your result has context from the first draw.

  2. Visit a partner lab

    Take your order to a certified Quest location for a short blood draw.

  3. Clinician review

    A licensed clinician reviews your result and shares clear interpretation with next steps.

FAQ

After ordering, visit a certified Quest partner location for a short blood draw. No insurance is required.

Feelrx / Start here

Know your baseline.

Order a panel online, draw at a certified partner lab, and receive a clear clinician review.

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