Ordering Recommendation




Quantitative Liquid Chromatography-Tandem Mass Spectrometry




1-4 days

New York DOH Approval Status

This test is New York DOH approved.

Specimen Required

Patient Preparation

Serum separator tube or plain red. Also acceptable: Lavender (EDTA) or pink (K2EDTA).

Specimen Preparation

Allow serum specimen to clot completely at room temperature. Separate serum or plasma from cells ASAP or within two hours of collection. Transfer 2 mL serum or plasma to an ARUP Standard Transport Tube. (Min: 1 mL)

Storage/Transport Temperature


Unacceptable Conditions

Grossly hemolyzed specimens.


After separation from cells: Ambient: 24 hours; Refrigerated: 1 week; Frozen: 3 months

Reference Interval

Test Number
Reference Interval
  Triiodothyronine, Reverse - LC-MS/MS
Age ng/dL
0-17 years Not Applicable
18 years and older 9.0-27.0

  Triiodothyronine, Total - LC-MS/MS
Age ng/dL
Cord Blood 14-86
0-3 days 96-292
4-30 days 62-243
1-23 months 81-281
2-6 years 83-252
7-11 years 92-219
12-19 years 83-215
20 years and older 80-200

  Triiodothyronine, Ratio (T3:RT3)
Age Ratio
0-17 years Not Applicable
18 years and older 4.2-11.0

Interpretive Data

This test was developed and its performance characteristics determined by ARUP Laboratories. It has not been cleared or approved by the US Food and Drug Administration. This test was performed in a CLIA certified laboratory and is intended for clinical purposes.

Compliance Category

Laboratory Developed Test (LDT)


Hotline History


CPT Codes

84480; 84482


Component Test Code* Component Chart Name LOINC
2007919 Triiodothyronine, Reverse - LC-MS/MS 3052-8
2008407 Triiodothyronine, Total - LC-MS/MS 3053-6
2008408 Triiodothyronine, Ratio (T3:RT3) 57899-7
* Component test codes cannot be used to order tests. The information provided here is not sufficient for interface builds; for a complete test mix, please click the sidebar link to access the Interface Map.


  • T3 total and reverse
  • Total and reversed Triiodothyronine T3 total and reverse
Triiodothyronine, Total and Triiodothyronine, Reverse with Ratio Calculation by Tandem Mass Spectrometry