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South · Reverse T3 Test – rT3 Testing

Reverse T3 Test – rT3 Testing in North Carolina

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 North Carolina

Here is what you need before ordering and completing the Reverse T3 Test – rT3 Testing in NC. 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 North Carolina communities

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

Charlotte1,516,107Reverse T3 Test – rT3 TestingRaleigh1,062,018Reverse T3 Test – rT3 TestingWinston-Salem420,400Reverse T3 Test – rT3 TestingDurham399,762Reverse T3 Test – rT3 TestingGreensboro345,270Reverse T3 Test – rT3 TestingFayetteville328,827Reverse T3 Test – rT3 TestingAsheville316,694Reverse T3 Test – rT3 TestingConcord264,492Reverse T3 Test – rT3 TestingWilmington247,372Reverse T3 Test – rT3 TestingHickory211,042Reverse T3 Test – rT3 TestingGastonia194,190Reverse T3 Test – rT3 TestingHigh Point178,800Reverse T3 Test – rT3 TestingCary171,603Reverse T3 Test – rT3 TestingBurlington137,096Reverse T3 Test – rT3 TestingGreenville122,921Reverse T3 Test – rT3 TestingJacksonville108,549Reverse T3 Test – rT3 TestingRocky Mount61,952Reverse T3 Test – rT3 TestingChapel Hill60,920Reverse T3 Test – rT3 TestingHuntersville60,166Reverse T3 Test – rT3 TestingApex58,066Reverse T3 Test – rT3 TestingKannapolis52,173Reverse T3 Test – rT3 TestingMooresville48,431Reverse T3 Test – rT3 TestingWilson47,914Reverse T3 Test – rT3 TestingWake Forest46,387Reverse T3 Test – rT3 TestingHolly Springs40,198Reverse T3 Test – rT3 TestingIndian Trail39,603Reverse T3 Test – rT3 TestingSalisbury35,258Reverse T3 Test – rT3 TestingMonroe34,464Reverse T3 Test – rT3 TestingGoldsboro33,214Reverse T3 Test – rT3 TestingFuquay-Varina33,135Reverse T3 Test – rT3 TestingNew Bern31,058Reverse T3 Test – rT3 TestingCornelius30,925Reverse T3 Test – rT3 TestingGarner30,859Reverse T3 Test – rT3 TestingSanford30,024Reverse T3 Test – rT3 TestingMatthews29,417Reverse T3 Test – rT3 TestingMorrisville28,824Reverse T3 Test – rT3 TestingStatesville27,777Reverse T3 Test – rT3 TestingThomasville26,941Reverse T3 Test – rT3 TestingAsheboro26,729Reverse T3 Test – rT3 TestingKernersville26,376Reverse T3 Test – rT3 TestingMint Hill26,236Reverse T3 Test – rT3 TestingClayton25,486Reverse T3 Test – rT3 TestingLeland22,794Reverse T3 Test – rT3 TestingShelby21,564Reverse T3 Test – rT3 TestingCarrboro21,237Reverse T3 Test – rT3 TestingClemmons21,032Reverse T3 Test – rT3 TestingKinston19,888Reverse T3 Test – rT3 TestingWaxhaw19,645Reverse T3 Test – rT3 TestingLexington19,347Reverse T3 Test – rT3 TestingLumberton19,186Reverse T3 Test – rT3 TestingKnightdale18,614Reverse T3 Test – rT3 TestingElizabeth City18,466Reverse T3 Test – rT3 TestingHarrisburg18,415Reverse T3 Test – rT3 TestingLenoir18,205Reverse T3 Test – rT3 TestingBoone18,055Reverse T3 Test – rT3 TestingHavelock17,570Reverse T3 Test – rT3 TestingHope Mills17,421Reverse T3 Test – rT3 TestingMorganton17,389Reverse T3 Test – rT3 TestingMount Holly17,315Reverse T3 Test – rT3 TestingPinehurst17,250Reverse T3 Test – rT3 Testing