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Midwest · Reverse T3 Test – rT3 Testing

Reverse T3 Test – rT3 Testing in Wisconsin

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 Wisconsin

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

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

Milwaukee1,340,981Reverse T3 Test – rT3 TestingMadison461,778Reverse T3 Test – rT3 TestingGreen Bay219,472Reverse T3 Test – rT3 TestingAppleton218,448Reverse T3 Test – rT3 TestingRacine135,352Reverse T3 Test – rT3 TestingKenosha123,061Reverse T3 Test – rT3 TestingEau Claire103,586Reverse T3 Test – rT3 TestingLa Crosse99,227Reverse T3 Test – rT3 TestingWausau76,016Reverse T3 Test – rT3 TestingOshkosh74,737Reverse T3 Test – rT3 TestingJanesville71,907Reverse T3 Test – rT3 TestingWaukesha71,307Reverse T3 Test – rT3 TestingSheboygan70,234Reverse T3 Test – rT3 TestingWest Bend69,672Reverse T3 Test – rT3 TestingWest Allis60,220Reverse T3 Test – rT3 TestingWauwatosa48,072Reverse T3 Test – rT3 TestingFond du Lac44,412Reverse T3 Test – rT3 TestingBrookfield41,020Reverse T3 Test – rT3 TestingNew Berlin40,289Reverse T3 Test – rT3 TestingMenomonee Falls38,219Reverse T3 Test – rT3 TestingGreenfield37,623Reverse T3 Test – rT3 TestingFranklin36,685Reverse T3 Test – rT3 TestingBeloit36,567Reverse T3 Test – rT3 TestingOak Creek36,266Reverse T3 Test – rT3 TestingSun Prairie35,528Reverse T3 Test – rT3 TestingManitowoc34,267Reverse T3 Test – rT3 TestingFitchburg29,361Reverse T3 Test – rT3 TestingMount Pleasant27,572Reverse T3 Test – rT3 TestingNeenah27,194Reverse T3 Test – rT3 TestingSuperior26,601Reverse T3 Test – rT3 TestingStevens Point25,752Reverse T3 Test – rT3 TestingCaledonia25,288Reverse T3 Test – rT3 TestingDe Pere25,216Reverse T3 Test – rT3 TestingMuskego24,991Reverse T3 Test – rT3 TestingMequon24,814Reverse T3 Test – rT3 TestingWatertown23,030Reverse T3 Test – rT3 TestingMiddleton21,634Reverse T3 Test – rT3 TestingPleasant Prairie21,193Reverse T3 Test – rT3 TestingSouth Milwaukee20,785Reverse T3 Test – rT3 TestingGermantown20,780Reverse T3 Test – rT3 TestingHoward19,828Reverse T3 Test – rT3 TestingFox Crossing18,907Reverse T3 Test – rT3 TestingOnalaska18,760Reverse T3 Test – rT3 TestingWisconsin Rapids18,711Reverse T3 Test – rT3 TestingMarshfield18,668Reverse T3 Test – rT3 TestingCudahy18,197Reverse T3 Test – rT3 TestingMenasha18,157Reverse T3 Test – rT3 TestingOconomowoc17,969Reverse T3 Test – rT3 TestingAshwaubenon17,042Reverse T3 Test – rT3 TestingKaukauna16,929Reverse T3 Test – rT3 TestingMenomonie16,721Reverse T3 Test – rT3 TestingBeaver Dam16,594Reverse T3 Test – rT3 TestingRiver Falls16,058Reverse T3 Test – rT3 TestingBellevue15,922Reverse T3 Test – rT3 TestingWeston15,609Reverse T3 Test – rT3 TestingHartford15,526Reverse T3 Test – rT3 TestingWhitefish Bay14,818Reverse T3 Test – rT3 TestingGreendale14,735Reverse T3 Test – rT3 TestingWaunakee14,679Reverse T3 Test – rT3 TestingSalem Lakes14,630Reverse T3 Test – rT3 Testing