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Mid-Atlantic · Reverse T3 Test – rT3 Testing

Reverse T3 Test – rT3 Testing in New York

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 New York

Here is what you need before ordering and completing the Reverse T3 Test – rT3 Testing in NY. 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, including NY. 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 New York communities

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

New York18,972,871Reverse T3 Test – rT3 TestingBrooklyn2,736,074Reverse T3 Test – rT3 TestingQueens2,405,464Reverse T3 Test – rT3 TestingManhattan1,694,263Reverse T3 Test – rT3 TestingBronx1,472,654Reverse T3 Test – rT3 TestingBuffalo1,004,655Reverse T3 Test – rT3 TestingRochester737,309Reverse T3 Test – rT3 TestingAlbany604,077Reverse T3 Test – rT3 TestingStaten Island495,747Reverse T3 Test – rT3 TestingPoughkeepsie423,386Reverse T3 Test – rT3 TestingSyracuse418,875Reverse T3 Test – rT3 TestingYonkers209,730Reverse T3 Test – rT3 TestingBinghamton146,870Reverse T3 Test – rT3 TestingUtica112,948Reverse T3 Test – rT3 TestingNew Rochelle80,685Reverse T3 Test – rT3 TestingMount Vernon72,855Reverse T3 Test – rT3 TestingSchenectady66,809Reverse T3 Test – rT3 TestingSaratoga Springs66,290Reverse T3 Test – rT3 TestingBrentwood66,035Reverse T3 Test – rT3 TestingGlens Falls66,024Reverse T3 Test – rT3 TestingElmira63,404Reverse T3 Test – rT3 TestingWhite Plains59,452Reverse T3 Test – rT3 TestingLevittown52,540Reverse T3 Test – rT3 TestingTroy50,717Reverse T3 Test – rT3 TestingNiagara Falls48,763Reverse T3 Test – rT3 TestingFreeport44,328Reverse T3 Test – rT3 TestingWest Babylon43,397Reverse T3 Test – rT3 TestingHicksville43,107Reverse T3 Test – rT3 TestingCoram41,431Reverse T3 Test – rT3 TestingValley Stream40,304Reverse T3 Test – rT3 TestingEast Meadow38,078Reverse T3 Test – rT3 TestingElmont36,741Reverse T3 Test – rT3 TestingCentral Islip36,292Reverse T3 Test – rT3 TestingCommack36,252Reverse T3 Test – rT3 TestingLong Beach34,820Reverse T3 Test – rT3 TestingNew City34,118Reverse T3 Test – rT3 TestingHuntington Station34,050Reverse T3 Test – rT3 TestingBaldwin33,352Reverse T3 Test – rT3 TestingSpring Valley32,953Reverse T3 Test – rT3 TestingUniondale32,791Reverse T3 Test – rT3 TestingKiryas Joel32,498Reverse T3 Test – rT3 TestingFranklin Square32,381Reverse T3 Test – rT3 TestingRome32,309Reverse T3 Test – rT3 TestingCentereach31,979Reverse T3 Test – rT3 TestingIthaca31,819Reverse T3 Test – rT3 TestingBay Shore31,488Reverse T3 Test – rT3 TestingPort Chester31,317Reverse T3 Test – rT3 TestingOceanside31,182Reverse T3 Test – rT3 TestingNorth Tonawanda30,592Reverse T3 Test – rT3 TestingMiddletown30,086Reverse T3 Test – rT3 TestingJamestown28,818Reverse T3 Test – rT3 TestingHarrison28,635Reverse T3 Test – rT3 TestingGlen Cove28,187Reverse T3 Test – rT3 TestingShirley28,059Reverse T3 Test – rT3 TestingWest Islip27,557Reverse T3 Test – rT3 TestingMonsey27,359Reverse T3 Test – rT3 TestingLindenhurst27,169Reverse T3 Test – rT3 TestingHolbrook26,958Reverse T3 Test – rT3 TestingAuburn26,913Reverse T3 Test – rT3 TestingDeer Park26,803Reverse T3 Test – rT3 Testing