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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

 

This test is not useful for general screening of the population without a clinical suspicion of hyperthyroidism.

Method Name

Electrochemiluminescence Immunoassay

Reporting Name

T3 (Triiodothyronine), Total, S

Specimen Type

Serum


Specimen Required


Patient Preparation: For 12 hours before specimen collection 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

0.75 mL

Specimen Stability Information

Specimen Type Temperature Time Special Container
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 www.mayocliniclabs.com/order-tests/si-unit-conversion.html

Day(s) Performed

Monday through Saturday

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 83124-8

 

Result ID Test Result Name Result LOINC Value
T3 T3 (Triiodothyronine), Total, S 83124-8

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.

Testing Algorithm

See Thyroid Function Ordering Algorithm in Special Instructions.

Report Available

Same day/1 to 3 days

NY State Approved

Yes