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Mid-Atlantic · Reverse T3 Test – rT3 Testing

Reverse T3 Test – rT3 Testing in Maryland

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 Maryland

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

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

Baltimore2,205,092Reverse T3 Test – rT3 TestingBel Air South222,834Reverse T3 Test – rT3 TestingHagerstown194,602Reverse T3 Test – rT3 TestingFrederick175,032Reverse T3 Test – rT3 TestingWaldorf119,442Reverse T3 Test – rT3 TestingSalisbury108,982Reverse T3 Test – rT3 TestingColumbia105,086Reverse T3 Test – rT3 TestingGermantown90,235Reverse T3 Test – rT3 TestingSilver Spring82,472Reverse T3 Test – rT3 TestingEllicott City74,432Reverse T3 Test – rT3 TestingEldersburg70,639Reverse T3 Test – rT3 TestingGlen Burnie69,739Reverse T3 Test – rT3 TestingGaithersburg68,827Reverse T3 Test – rT3 TestingRockville67,095Reverse T3 Test – rT3 TestingDundalk66,426Reverse T3 Test – rT3 TestingBethesda66,294Reverse T3 Test – rT3 TestingTowson59,014Reverse T3 Test – rT3 TestingBowie58,113Reverse T3 Test – rT3 TestingSevern53,955Reverse T3 Test – rT3 TestingAspen Hill53,850Reverse T3 Test – rT3 TestingWheaton51,836Reverse T3 Test – rT3 TestingNorth Bethesda50,695Reverse T3 Test – rT3 TestingPotomac46,891Reverse T3 Test – rT3 TestingOdenton43,488Reverse T3 Test – rT3 TestingCatonsville42,789Reverse T3 Test – rT3 TestingWoodlawn42,053Reverse T3 Test – rT3 TestingEssex40,710Reverse T3 Test – rT3 TestingAnnapolis40,581Reverse T3 Test – rT3 TestingClinton39,925Reverse T3 Test – rT3 TestingSeverna Park39,108Reverse T3 Test – rT3 TestingChillum36,428Reverse T3 Test – rT3 TestingOlney35,815Reverse T3 Test – rT3 TestingRandallstown35,641Reverse T3 Test – rT3 TestingOwings Mills35,170Reverse T3 Test – rT3 TestingCollege Park34,961Reverse T3 Test – rT3 TestingMontgomery Village34,489Reverse T3 Test – rT3 TestingPikesville33,549Reverse T3 Test – rT3 TestingPasadena31,583Reverse T3 Test – rT3 TestingBel Air North30,969Reverse T3 Test – rT3 TestingParkville30,783Reverse T3 Test – rT3 TestingMilford Mill30,685Reverse T3 Test – rT3 TestingMiddle River30,606Reverse T3 Test – rT3 TestingCarney29,873Reverse T3 Test – rT3 TestingCrofton29,812Reverse T3 Test – rT3 TestingLaurel29,438Reverse T3 Test – rT3 TestingPerry Hall29,165Reverse T3 Test – rT3 TestingSouth Laurel27,998Reverse T3 Test – rT3 TestingReisterstown27,917Reverse T3 Test – rT3 TestingIlchester27,513Reverse T3 Test – rT3 TestingClarksburg27,354Reverse T3 Test – rT3 TestingLochearn26,995Reverse T3 Test – rT3 TestingSuitland26,375Reverse T3 Test – rT3 TestingFort Washington25,840Reverse T3 Test – rT3 TestingFairland25,324Reverse T3 Test – rT3 TestingArnold25,056Reverse T3 Test – rT3 TestingEdgewood25,004Reverse T3 Test – rT3 TestingGreenbelt24,602Reverse T3 Test – rT3 TestingLandover24,508Reverse T3 Test – rT3 TestingNorth Potomac24,449Reverse T3 Test – rT3 TestingNorth Laurel24,233Reverse T3 Test – rT3 Testing