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Pacific · Reverse T3 Test – rT3 Testing

Reverse T3 Test – rT3 Testing in Alaska

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 Alaska

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

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

Anchorage292,545Reverse T3 Test – rT3 TestingFairbanks64,160Reverse T3 Test – rT3 TestingJuneau32,240Reverse T3 Test – rT3 TestingBadger19,226Reverse T3 Test – rT3 TestingKnik-Fairview18,282Reverse T3 Test – rT3 TestingCollege11,797Reverse T3 Test – rT3 TestingTanaina10,314Reverse T3 Test – rT3 TestingNorth Lakes9,941Reverse T3 Test – rT3 TestingWasilla9,098Reverse T3 Test – rT3 TestingSitka8,518Reverse T3 Test – rT3 TestingKalifornsky8,428Reverse T3 Test – rT3 TestingMeadow Lakes8,367Reverse T3 Test – rT3 TestingKetchikan8,150Reverse T3 Test – rT3 TestingKenai7,452Reverse T3 Test – rT3 TestingSteele Creek7,399Reverse T3 Test – rT3 TestingSouth Lakes6,421Reverse T3 Test – rT3 TestingGateway6,305Reverse T3 Test – rT3 TestingBethel6,273Reverse T3 Test – rT3 TestingSterling6,016Reverse T3 Test – rT3 TestingPalmer5,978Reverse T3 Test – rT3 TestingKodiak5,682Reverse T3 Test – rT3 TestingChena Ridge5,643Reverse T3 Test – rT3 TestingHomer5,531Reverse T3 Test – rT3 TestingUtqiagvik5,123Reverse T3 Test – rT3 TestingFishhook5,055Reverse T3 Test – rT3 TestingSoldotna4,370Reverse T3 Test – rT3 TestingUnalaska4,339Reverse T3 Test – rT3 TestingNikiski4,232Reverse T3 Test – rT3 TestingFarmers Loop4,216Reverse T3 Test – rT3 TestingValdez3,966Reverse T3 Test – rT3 TestingButte3,857Reverse T3 Test – rT3 TestingMill Bay3,719Reverse T3 Test – rT3 TestingNome3,685Reverse T3 Test – rT3 TestingPetersburg3,259Reverse T3 Test – rT3 TestingEielson AFB3,240Reverse T3 Test – rT3 TestingKotzebue3,199Reverse T3 Test – rT3 TestingBig Lake2,888Reverse T3 Test – rT3 TestingNorth Pole2,825Reverse T3 Test – rT3 TestingGoldstream2,822Reverse T3 Test – rT3 TestingEster2,719Reverse T3 Test – rT3 TestingRidgeway2,689Reverse T3 Test – rT3 TestingSeward2,614Reverse T3 Test – rT3 TestingCordova2,588Reverse T3 Test – rT3 TestingFarm Loop2,549Reverse T3 Test – rT3 TestingAnchor Point2,288Reverse T3 Test – rT3 TestingKodiak Station2,183Reverse T3 Test – rT3 TestingWrangell2,162Reverse T3 Test – rT3 TestingFritz Creek2,145Reverse T3 Test – rT3 TestingDillingham2,133Reverse T3 Test – rT3 TestingDeltana2,022Reverse T3 Test – rT3 TestingWillow1,965Reverse T3 Test – rT3 TestingLazy Mountain1,766Reverse T3 Test – rT3 TestingHouston1,739Reverse T3 Test – rT3 TestingHaines1,571Reverse T3 Test – rT3 TestingCohoe1,557Reverse T3 Test – rT3 TestingBear Creek1,524Reverse T3 Test – rT3 TestingPrudhoe Bay1,500Reverse T3 Test – rT3 TestingMetlakatla1,445Reverse T3 Test – rT3 TestingDiamond Ridge1,409Reverse T3 Test – rT3 TestingPoint MacKenzie1,364Reverse T3 Test – rT3 Testing