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Test Code LAB137 T3 Free

Clinical Information

Free T3 is not a sensitive test for hypothyroidism. Performance of this assay has not been established with neonatal specimens. For assays employing antibodies, the possibility exists for interference by human anti-animal antibodies (i.e., heterophile antibodies) in the patient sample. Patients who have been regularly exposed to animals or have received immunotherapy or diagnostic procedures utilizing immunoglobulins or immunoglobulin fragments may produce antibodies, (eg, HAMA), that interfere with immunoassays. This may falsely elevate or falsely decrease the results.

Synonym

  • FT3

Specimen Required

Preferred Container/Tube: Mint Green Top
Acceptable Container/Tube: Mint Green Top, Gold SST Top
Specimen Volume: 3 mL
Specimen Minimum Volume: 1 mL

Specimen Stability Information

Ambient: 8 hours
Refrigerated: 5 days

Rejected Due To

  • Gross hemolysis

Reference Values

FEMALE MALE
0-3 days: 1.4-5.4 pg/mL
4-29 days: 1.5-5.0 pg/mL
30-365 days: 2.5-6.5 pg/mL
1-5 years: 3.0-6.0 pg/mL
6-10 years: 2.7-6.2 pg/mL
11-15 years: 2.6-5.7 pg/mL
16-18 years: 2.8-5.2 pg/mL
19+ years: 2.3-4.2 pg/mL		 0-3 days: 1.4-4.8 pg/mL
4-29 days: 1.4-5.5 pg/mL
30-365 days: 2.0-6.9 pg/mL
1-5 years: 2.4-6.7 pg/mL
6-10 years: 2.9-6.0 pg/mL
11-15 years: 3.1-5.9 pg/mL
16-18 years: 3.5-5.7 pg/mL
19+ years: 2.3-4.2 pg/mL

Method Description

Competitive immunoassay using direct chemiluminescent technology.

Performing Lab

Clinical Lab UH

Day(s) Performed

Monday through Sunday

Report Available

Same day/1 day

Reporting Name

T3 Free

CPT Code Information

84481

LOINC Code Information

3051-0