Test Overview
Test Methodology

Liquid Chromatography-Tandem Mass Spectrometry (LC-MS/MS)

Test Usage

In hospitalized or sick patients with low triiodothyronine (T3) values, elevated reverse triiodothyronine (rT3) values are consistent with "sick euthyroid" syndrome. Also, the finding on an elevated rT3 level in a critically ill patient helps exclude a diagnosis of hypothyroidism.

Reference Range *

9 - 27.0 ng/dL

Test Details
Days Set Up
Monday, Wednesday, Friday
Analytic Time

4 - 6 days

Soft Order Code
RT3
MiChart Code
T3, Reverse
Synonyms
  • Triiodothyronine, Reverse
  • Reverse T3 (Triiodothyronine)
  • T3 (Triiodothyronine), Reverse
  • RET3
  • RT3
  • Reverse T3, S
Laboratory
Sendout
Reference Laboratory
Warde RT3
Section
Special Testing
Specimen Requirements
Collection Instructions

Collect specimen in a red top tube. Centrifuge, aliquot serum into a plastic vial within 2 hours of collection, and refrigerate.

Yellow Top Tube
Normal Volume
1.0 mL
Minimum Volume
0.5 mL
Additional Information

Test sent to Warde Medical Laboratory.

Billing
CPT Code
84482
Fee Code
32011
LOINC
3052-8
NY State Approved
No