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South · Reverse T3 Test – rT3 Testing

Reverse T3 Test – rT3 Testing in Louisiana

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 Louisiana

Here is what you need before ordering and completing the Reverse T3 Test – rT3 Testing in LA. 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 Louisiana communities

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

New Orleans925,443Reverse T3 Test – rT3 TestingBaton Rouge610,751Reverse T3 Test – rT3 TestingShreveport286,200Reverse T3 Test – rT3 TestingLafayette254,286Reverse T3 Test – rT3 TestingLake Charles150,036Reverse T3 Test – rT3 TestingHouma146,665Reverse T3 Test – rT3 TestingMetairie140,590Reverse T3 Test – rT3 TestingMonroe117,197Reverse T3 Test – rT3 TestingMandeville105,097Reverse T3 Test – rT3 TestingSlidell94,498Reverse T3 Test – rT3 TestingAlexandria75,835Reverse T3 Test – rT3 TestingHammond75,688Reverse T3 Test – rT3 TestingKenner66,411Reverse T3 Test – rT3 TestingBossier City63,168Reverse T3 Test – rT3 TestingPrairieville34,118Reverse T3 Test – rT3 TestingMarrero31,928Reverse T3 Test – rT3 TestingCentral29,746Reverse T3 Test – rT3 TestingLaplace29,129Reverse T3 Test – rT3 TestingNew Iberia28,844Reverse T3 Test – rT3 TestingTerrytown25,388Reverse T3 Test – rT3 TestingRuston22,286Reverse T3 Test – rT3 TestingChalmette21,981Reverse T3 Test – rT3 TestingBayou Cane21,699Reverse T3 Test – rT3 TestingSulphur21,490Reverse T3 Test – rT3 TestingHarvey20,942Reverse T3 Test – rT3 TestingShenandoah20,068Reverse T3 Test – rT3 TestingZachary19,278Reverse T3 Test – rT3 TestingNatchitoches18,105Reverse T3 Test – rT3 TestingGretna17,836Reverse T3 Test – rT3 TestingEstelle17,650Reverse T3 Test – rT3 TestingOpelousas15,884Reverse T3 Test – rT3 TestingThibodaux15,242Reverse T3 Test – rT3 TestingYoungsville15,167Reverse T3 Test – rT3 TestingPineville14,653Reverse T3 Test – rT3 TestingLuling14,115Reverse T3 Test – rT3 TestingRiver Ridge13,435Reverse T3 Test – rT3 TestingClaiborne13,147Reverse T3 Test – rT3 TestingWest Monroe13,103Reverse T3 Test – rT3 TestingBroussard12,960Reverse T3 Test – rT3 TestingBaker12,736Reverse T3 Test – rT3 TestingMinden12,145Reverse T3 Test – rT3 TestingGonzales12,080Reverse T3 Test – rT3 TestingCrowley11,916Reverse T3 Test – rT3 TestingDestrehan11,827Reverse T3 Test – rT3 TestingMorgan City11,525Reverse T3 Test – rT3 TestingMoss Bluff11,453Reverse T3 Test – rT3 TestingWoodmere11,343Reverse T3 Test – rT3 TestingAbbeville11,313Reverse T3 Test – rT3 TestingBayou Blue11,229Reverse T3 Test – rT3 TestingWaggaman11,161Reverse T3 Test – rT3 TestingCovington11,155Reverse T3 Test – rT3 TestingRaceland11,002Reverse T3 Test – rT3 TestingGardere10,971Reverse T3 Test – rT3 TestingBogalusa10,921Reverse T3 Test – rT3 TestingTimberlane10,697Reverse T3 Test – rT3 TestingJefferson10,500Reverse T3 Test – rT3 TestingBelle Chasse10,406Reverse T3 Test – rT3 TestingDeRidder10,060Reverse T3 Test – rT3 TestingBastrop9,879Reverse T3 Test – rT3 TestingJennings9,836Reverse T3 Test – rT3 Testing