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Mountain West · Reverse T3 Test – rT3 Testing

Reverse T3 Test – rT3 Testing in Utah

This page explains the reverse t3 test – rt3 testing, what it measures, and how to order it. The Reverse T3 blood test measures a form of thyroid hormone that can help clarify unusual thyroid function test results. It is often used alongside other thyroid tests to give a fuller picture of how the body is handling thyroid hormone.

Sample typeBlood and/or urine at a collection lab
ReferralIncluded — no referral from your own doctor needed

Lab requirements in Utah

Here is what you need before ordering and completing the Reverse T3 Test – rT3 Testing in UT. Review each item and confirm the details with the collection lab.

Physician's order
Included. A physician's order is required for lab testing and is provided for you by our partner's physicians — no referral from your own doctor is needed.
Fasting
Some tests require fasting or avoiding certain foods or drinks beforehand. You will be informed when you order — confirm the details with the collection lab.
Preparation
Preparation instructions can vary depending on the laboratory and the other tests being performed at the same time. Always follow the specific instructions provided by the collection lab or…
Sample & visit
A blood and/or urine sample is collected; the visit usually takes about 10 minutes.
Identification
Bring the lab requisition form from your account. The collection lab may also ask for a government-issued photo ID.
Turnaround
1-3 business days
Availability
Our partner lab does not serve ND, RI, NY, NJ, MD or HI. Confirm availability for your location with the collection lab.

Before you go

  • Order your test before visiting a lab, then use the requisition form in your account.
  • Print the requisition form, or fax it to the lab directly from your account.
  • No scheduling is needed — visit the collection lab during its normal business hours.
  • A blood and/or urine sample is collected; the visit usually takes about 10 minutes.
  • Bring a government-issued photo ID in case the lab requests it.
  • Results are posted to your secure account within 1–3 business days.

Requirements are summarized from our partner lab's published policies. Preparation and availability can change — confirm current instructions with the collection lab before your visit.

What this test is

Reverse T3 is a biologically inactive form of thyroid hormone produced when the body converts thyroxine (T4) in an alternative pathway. This test measures the amount of reverse T3 circulating in the blood. It is not a stand-alone diagnostic test but is interpreted with other thyroid hormone measurements.

What it measures

  • Reverse T3 — reflects the amount of this inactive thyroid hormone form in the blood
  • Total T3 — often measured alongside to assess active thyroid hormone levels
  • Free T4 — helps evaluate the main thyroid hormone produced by the thyroid gland
  • TSH — indicates how the pituitary gland is responding to thyroid hormone levels

What the test involves

A healthcare professional collects a small sample of blood, usually from a vein in your arm, using a standard blood draw. The sample is then sent to a laboratory for analysis.

Why it is often ordered

A clinician may order a reverse T3 test when thyroid test results are confusing or when a nonthyroidal illness is suspected. It is typically used to help evaluate whether symptoms or abnormal thyroid tests might be related to how the body is converting thyroid hormones.

Preparation

Preparation instructions can vary depending on the laboratory and the other tests being performed at the same time. Always follow the specific instructions provided by the collection lab or your healthcare provider.

How results are reported

Results are reported as a numeric value for reverse T3, and the laboratory will provide a reference range for comparison. Reference ranges can differ between laboratories because of differences in equipment, methods, and population, so your result should be interpreted using the range from the lab that performed the test.

Before you go

  • Whether any other tests will be drawn at the same time and if fasting is required.
  • The specific reference range used by the laboratory performing the test.
  • How and when you will receive your results.

Cities

Reverse T3 Test – rT3 Testing in Utah communities

Choose your city for local context and to order this test.

Salt Lake City1,135,344Reverse T3 Test – rT3 TestingOgden608,259Reverse T3 Test – rT3 TestingProvo551,645Reverse T3 Test – rT3 TestingWest Valley City139,361Reverse T3 Test – rT3 TestingSt. George127,890Reverse T3 Test – rT3 TestingWest Jordan116,045Reverse T3 Test – rT3 TestingLogan106,319Reverse T3 Test – rT3 TestingOrem96,734Reverse T3 Test – rT3 TestingSandy96,272Reverse T3 Test – rT3 TestingLayton80,858Reverse T3 Test – rT3 TestingSouth Jordan75,617Reverse T3 Test – rT3 TestingLehi73,911Reverse T3 Test – rT3 TestingMillcreek63,430Reverse T3 Test – rT3 TestingTaylorsville60,295Reverse T3 Test – rT3 TestingHerriman52,860Reverse T3 Test – rT3 TestingMurray50,183Reverse T3 Test – rT3 TestingDraper49,978Reverse T3 Test – rT3 TestingBountiful45,496Reverse T3 Test – rT3 TestingRiverton44,773Reverse T3 Test – rT3 TestingEagle Mountain42,905Reverse T3 Test – rT3 TestingSpanish Fork41,953Reverse T3 Test – rT3 TestingRoy39,076Reverse T3 Test – rT3 TestingPleasant Grove37,228Reverse T3 Test – rT3 TestingSaratoga Springs36,977Reverse T3 Test – rT3 TestingKearns36,842Reverse T3 Test – rT3 TestingMidvale35,313Reverse T3 Test – rT3 TestingTooele35,223Reverse T3 Test – rT3 TestingSpringville34,750Reverse T3 Test – rT3 TestingCedar City34,246Reverse T3 Test – rT3 TestingCottonwood Heights33,597Reverse T3 Test – rT3 TestingAmerican Fork32,822Reverse T3 Test – rT3 TestingKaysville32,438Reverse T3 Test – rT3 TestingClearfield31,802Reverse T3 Test – rT3 TestingHolladay31,738Reverse T3 Test – rT3 TestingSyracuse31,715Reverse T3 Test – rT3 TestingMagna29,128Reverse T3 Test – rT3 TestingWashington27,689Reverse T3 Test – rT3 TestingSouth Salt Lake26,086Reverse T3 Test – rT3 TestingFarmington23,990Reverse T3 Test – rT3 TestingClinton23,192Reverse T3 Test – rT3 TestingNorth Salt Lake21,411Reverse T3 Test – rT3 TestingPayson21,093Reverse T3 Test – rT3 TestingNorth Ogden20,703Reverse T3 Test – rT3 TestingHurricane19,501Reverse T3 Test – rT3 TestingBrigham City19,373Reverse T3 Test – rT3 TestingHighland18,913Reverse T3 Test – rT3 TestingSouth Ogden17,363Reverse T3 Test – rT3 TestingWest Haven16,918Reverse T3 Test – rT3 TestingCenterville16,711Reverse T3 Test – rT3 TestingBluffdale16,576Reverse T3 Test – rT3 TestingHeber16,416Reverse T3 Test – rT3 TestingSantaquin13,602Reverse T3 Test – rT3 TestingSmithfield13,263Reverse T3 Test – rT3 TestingGrantsville12,331Reverse T3 Test – rT3 TestingVineyard11,579Reverse T3 Test – rT3 TestingWoods Cross11,372Reverse T3 Test – rT3 TestingLindon11,346Reverse T3 Test – rT3 TestingMapleton11,226Reverse T3 Test – rT3 TestingWest Point10,963Reverse T3 Test – rT3 TestingPleasant View10,733Reverse T3 Test – rT3 Testing