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Test ID T3 T3 (Triiodothyronine), Total, Serum

Useful For

Second-order testing for hyperthyroidism in patients with low thyroid-stimulating hormone values and normal thyroxine levels

 

Diagnosis of triiodothyronine toxicosis

Method Name

Electrochemiluminescence Immunoassay

Reporting Name

T3 (Triiodothyronine), Total, S

Specimen Type

Serum


Specimen Required


Patient Preparation: For 12 hours before this test do not take multivitamins or dietary supplements containing biotin (vitamin B7), which is commonly found in hair, skin, and nail supplements and multivitamins.

Container/Tube:

Preferred: Serum gel

Acceptable: Red top

Submission Container/Tube: Plastic vial

Specimen Volume: 1 mL


Specimen Minimum Volume

0.5 mL

Specimen Stability Information

Specimen Type Temperature Time
Serum Refrigerated (preferred) 7 days
  Frozen  30 days

Reference Values

Pediatric

0-5 days: 73-288 ng/dL

6 days-2 months: 80-275 ng/dL

3-11 months: 86-265 ng/dL

1-5 years: 92-248 ng/dL

6-10 years: 93-231 ng/dL

11-19 years: 91-218 ng/dL

 

Adult (≥20 years): 80-200 ng/dL

 

For SI unit Reference Values, see https://www.mayocliniclabs.com/order-tests/si-unit-conversion.html

Day(s) and Time(s) Performed

Monday through Friday; 5 a.m.-12 a.m.

Saturday; 6 a.m.-6 p.m.

Performing Laboratory

Mayo Clinic Laboratories in Rochester

CPT Code Information

84480

LOINC Code Information

Test ID Test Order Name Order LOINC Value
T3 T3 (Triiodothyronine), Total, S 3053-6

 

Result ID Test Result Name Result LOINC Value
T3 T3 (Triiodothyronine), Total, S 3053-6

Test Classification

This test has been cleared or approved by the U.S. 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.

Testing Algorithm

See Thyroid Function Ordering Algorithm in Special Instructions.