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Test Code LAB137 T3, Free

Important Note

This test is not Reverse T3 or Total T3.

Reverse T3 is sent to Mayo and is ordered as a LAB3488.

Total T3 is done at PRMC and is ordered as LAB136.

Additional Codes

CPT Code: 84481

Performing Laboratory

TidalHealth Peninsula Regional - Core Laboratory: Chemistry

Specimen Requirements

Plasma
Draw blood in a green-top (lithium heparin) tube. (EDTA and Sodium Heparin plasma are not acceptable.) Spin down and separate 1 mL of plasma. Refrigerate if test will not be performed within 2 hours. Keep at refrigerated temperatures during courier transport.

 

Serum (Not preferred)

Draw blood in a gold top tube. Plain red and tiger top SST are acceptable. Allow plain red to clot before centrifugation, otherwise centrifuge immediately after collection. If sample does not have gel barrier, promptly seperate from contact with cells after centrifugation and send a 1 mL aliquot of serum. Keep at refrigerated temperatures during courier transport.

Reference Values

0-2 months: 4.7-5.4 pg/mL

2 months - 2 years: 5.7-6.4 pg/mL

2-7 years: 5.3-6.2 pg/mL

7-12 years: 5.0-6.0 pg/mL

12-20 years: 4.8-6.0 pg/mL

> 20 years: 2.0-4.4 pg/mL

 

Methodology

Electrochemiluminescence immunoassay (ECLIA)