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Test Code T3FR T3 (Triiodothyronine), Free, Serum


Specimen Required


Supplies: Sarstedt Aliquot Tube, 5 mL (T914)

Collection Container/Tube:

Preferred: Serum gel

Acceptable: Red top

Submission Container/Tube: Plastic vial

Specimen Volume: 1 mL

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


Useful For

A second- or third-level test of thyroid function

 

Confirmation of hyperthyroidism, supplementing the T4 (tetraiodothyronine), sensitive thyrotropin, and total T3 assays

 

Evaluating clinically euthyroid patients who have an altered distribution of binding proteins

Method Name

Electrochemiluminescence Immunoassay (ECLIA)

Reporting Name

T3 (Triiodothyronine), Free, S

Specimen Type

Serum

Specimen Minimum Volume

0.75 mL

Specimen Stability Information

Specimen Type Temperature Time Special Container
Serum Refrigerated (preferred) 14 days
  Frozen  30 days

Reference Values

Pediatric

0-1 month: 2.7-8.5 pg/mL

1-<12 months: 3.4-5.6 pg/mL

1-<14 years: 3.0-5.1 pg/mL

14-<19 years: 3.3-5.3 pg/mL

 

Adult (≥19 years): 2.0-4.4 pg/mL

 

For International System of Units (SI) conversion for Reference Values, see www.mayocliniclabs.com/order-tests/si-unit-conversion.html.

Day(s) Performed

Monday through Saturday

Report Available

1 to 3 days

Performing Laboratory

Mayo Clinic Laboratories in Rochester

Test Classification

This test has been cleared, approved, or is exempt by the US Food and Drug Administration and is used per manufacturer's instructions. Performance characteristics were verified by Mayo Clinic in a manner consistent with CLIA requirements.

CPT Code Information

84481

LOINC Code Information

Test ID Test Order Name Order LOINC Value
T3FR T3 (Triiodothyronine), Free, S 3051-0

 

Result ID Test Result Name Result LOINC Value
T3FR T3 (Triiodothyronine), Free, S 3051-0