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Test Code REVT3 T3 (Triiodothyronine), Reverse, Serum

Important Note

Effective Date: 4/7/26

Mayo Test ID: RT3

Due to concerns around acceptable turnaround times, RT3 will be placed test down immediately. Pending samples received at Mayo Clinic Laboratories will be performed by Mayo Clinic Laboratories with extended turnaround times. The test down is indefinite.

Recommended Alternative Test: FRT3S

Additional Codes

 

Mayo Code
RT3
Epic Code
LAB3266
LIS Code
REVT3

 

Test Down Notes

This test is temporarily unavailable due to concerns around acceptable turnaround times. Order FRT3S as an alternative.

Reporting Name

T3 (Triiodothyronine), Reverse, S

Useful For

Aiding in the diagnosis of the sick euthyroid syndrome

Performing Laboratory

Mayo Clinic Laboratories in Rochester

Specimen Type

Serum


Specimen Required


Supplies: Sarstedt Aliquot Tube, 5 mL (T914)

Collection Container/Tube:

Preferred: Red top

Acceptable: Serum gel

Submission Container/Tube: Plastic vial

Specimen Volume: 0.8 mL

Collection Instructions: Centrifuge and aliquot serum into a plastic vial.


Specimen Minimum Volume

0.4 mL

Specimen Stability Information

Specimen Type Temperature Time
Serum Refrigerated (preferred) 28 days
  Ambient  28 days
  Frozen  28 days

Reject Due To

Gross hemolysis Reject
Gross lipemia OK
Gross icterus OK

Reference Values

10-24 ng/dL

Day(s) Performed

Monday through Friday

Test Classification

This test was developed and its performance characteristics determined by Mayo Clinic in a manner consistent with CLIA requirements. It has not been cleared or approved by the US Food and Drug Administration.

CPT Code Information

84482

LOINC Code Information

Test ID Test Order Name Order LOINC Value
RT3 T3 (Triiodothyronine), Reverse, S 3052-8

 

Result ID Test Result Name Result LOINC Value
9405 T3(Triiodothyronine),Reverse,S 3052-8

Report Available

2 to 6 days

Forms

If not ordering electronically, complete, print, and send 1 of the following forms with the specimen:

-General Request (T239)

-Renal Diagnostics Test Request (T830)