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Mid-Atlantic · Reverse T3 Test – rT3 Testing

Reverse T3 Test – rT3 Testing in Delaware

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 Delaware

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

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

Dover125,931Reverse T3 Test – rT3 TestingWilmington70,926Reverse T3 Test – rT3 TestingNewark31,393Reverse T3 Test – rT3 TestingMiddletown23,001Reverse T3 Test – rT3 TestingBear21,625Reverse T3 Test – rT3 TestingGlasgow15,342Reverse T3 Test – rT3 TestingBrookside14,202Reverse T3 Test – rT3 TestingHockessin13,464Reverse T3 Test – rT3 TestingSmyrna12,619Reverse T3 Test – rT3 TestingPike Creek Valley11,718Reverse T3 Test – rT3 TestingMilford11,249Reverse T3 Test – rT3 TestingClaymont9,508Reverse T3 Test – rT3 TestingWilmington Manor8,212Reverse T3 Test – rT3 TestingNorth Star8,009Reverse T3 Test – rT3 TestingSeaford7,852Reverse T3 Test – rT3 TestingPike Creek7,398Reverse T3 Test – rT3 TestingGeorgetown7,079Reverse T3 Test – rT3 TestingEdgemoor6,681Reverse T3 Test – rT3 TestingMillsboro6,542Reverse T3 Test – rT3 TestingElsmere6,167Reverse T3 Test – rT3 TestingNew Castle5,482Reverse T3 Test – rT3 TestingHighland Acres3,910Reverse T3 Test – rT3 TestingLaurel3,886Reverse T3 Test – rT3 TestingClayton3,845Reverse T3 Test – rT3 TestingCamden3,786Reverse T3 Test – rT3 TestingRising Sun-Lebanon3,772Reverse T3 Test – rT3 TestingHarrington3,730Reverse T3 Test – rT3 TestingLewes3,257Reverse T3 Test – rT3 TestingMilton3,224Reverse T3 Test – rT3 TestingDover Base Housing3,135Reverse T3 Test – rT3 TestingLong Neck3,022Reverse T3 Test – rT3 TestingSelbyville2,806Reverse T3 Test – rT3 TestingGreenville2,763Reverse T3 Test – rT3 TestingTownsend2,671Reverse T3 Test – rT3 TestingOcean View2,556Reverse T3 Test – rT3 TestingBridgeville2,499Reverse T3 Test – rT3 TestingDelmar2,241Reverse T3 Test – rT3 TestingRiverview2,091Reverse T3 Test – rT3 TestingDelaware City1,885Reverse T3 Test – rT3 TestingWoodside East1,867Reverse T3 Test – rT3 TestingMillville1,790Reverse T3 Test – rT3 TestingKent Acres1,756Reverse T3 Test – rT3 TestingCheswold1,705Reverse T3 Test – rT3 TestingWyoming1,636Reverse T3 Test – rT3 TestingRodney Village1,472Reverse T3 Test – rT3 TestingGreenwood1,459Reverse T3 Test – rT3 TestingRehoboth Beach1,392Reverse T3 Test – rT3 TestingBellefonte1,294Reverse T3 Test – rT3 TestingNewport1,224Reverse T3 Test – rT3 TestingSt. Georges1,197Reverse T3 Test – rT3 TestingFelton1,144Reverse T3 Test – rT3 TestingFrankford1,088Reverse T3 Test – rT3 TestingDagsboro1,087Reverse T3 Test – rT3 Testing