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South · Reverse T3 Test – rT3 Testing

Reverse T3 Test – rT3 Testing in Kentucky

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 Kentucky

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

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

Louisville1,022,630Reverse T3 Test – rT3 TestingLexington321,354Reverse T3 Test – rT3 TestingBowling Green98,537Reverse T3 Test – rT3 TestingElizabethtown78,446Reverse T3 Test – rT3 TestingOwensboro73,115Reverse T3 Test – rT3 TestingCovington40,930Reverse T3 Test – rT3 TestingGeorgetown36,281Reverse T3 Test – rT3 TestingRichmond34,662Reverse T3 Test – rT3 TestingFlorence31,699Reverse T3 Test – rT3 TestingNicholasville31,066Reverse T3 Test – rT3 TestingHopkinsville30,771Reverse T3 Test – rT3 TestingJeffersontown28,800Reverse T3 Test – rT3 TestingFrankfort28,479Reverse T3 Test – rT3 TestingIndependence28,256Reverse T3 Test – rT3 TestingHenderson28,201Reverse T3 Test – rT3 TestingPaducah26,248Reverse T3 Test – rT3 TestingRadcliff22,839Reverse T3 Test – rT3 TestingAshland21,695Reverse T3 Test – rT3 TestingMadisonville19,533Reverse T3 Test – rT3 TestingErlanger19,506Reverse T3 Test – rT3 TestingWinchester18,993Reverse T3 Test – rT3 TestingBurlington18,394Reverse T3 Test – rT3 TestingMount Washington17,723Reverse T3 Test – rT3 TestingSt. Matthews17,588Reverse T3 Test – rT3 TestingFort Thomas17,241Reverse T3 Test – rT3 TestingMurray17,241Reverse T3 Test – rT3 TestingDanville17,164Reverse T3 Test – rT3 TestingShelbyville16,932Reverse T3 Test – rT3 TestingShively15,638Reverse T3 Test – rT3 TestingBerea15,465Reverse T3 Test – rT3 TestingGlasgow14,922Reverse T3 Test – rT3 TestingNewport14,378Reverse T3 Test – rT3 TestingShepherdsville13,918Reverse T3 Test – rT3 TestingBardstown13,425Reverse T3 Test – rT3 TestingFort Campbell North13,323Reverse T3 Test – rT3 TestingSomerset11,696Reverse T3 Test – rT3 TestingLawrenceburg11,675Reverse T3 Test – rT3 TestingCampbellsville11,345Reverse T3 Test – rT3 TestingLyndon11,033Reverse T3 Test – rT3 TestingParis10,202Reverse T3 Test – rT3 TestingVersailles10,196Reverse T3 Test – rT3 TestingAlexandria10,125Reverse T3 Test – rT3 TestingFrancisville10,088Reverse T3 Test – rT3 TestingMayfield10,041Reverse T3 Test – rT3 TestingLa Grange9,901Reverse T3 Test – rT3 TestingFranklin9,885Reverse T3 Test – rT3 TestingOakbrook9,883Reverse T3 Test – rT3 TestingMiddlesborough9,493Reverse T3 Test – rT3 TestingMiddletown9,473Reverse T3 Test – rT3 TestingElsmere9,080Reverse T3 Test – rT3 TestingHarrodsburg8,952Reverse T3 Test – rT3 TestingFort Knox8,888Reverse T3 Test – rT3 TestingMaysville8,851Reverse T3 Test – rT3 TestingHillview8,638Reverse T3 Test – rT3 TestingFort Mitchell8,618Reverse T3 Test – rT3 TestingEdgewood8,427Reverse T3 Test – rT3 TestingCorbin8,397Reverse T3 Test – rT3 TestingOak Grove7,699Reverse T3 Test – rT3 TestingMount Sterling7,517Reverse T3 Test – rT3 TestingLondon7,492Reverse T3 Test – rT3 Testing