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Test Code FT3CC T3, Free

Specimen Stability

8 hours at room temperature

2 days refrigerated at 2-8°C

Freeze at ≤ -20°C for longer storage

Do not use specimens stored at room temperature for longer than 8 hours.

Minimum Volume

0.5 mL

Reference Values

2.0 - 4.4 pg/ml

Day(s) Test Performed

Monday - Sunday

Specimen Requirement

High doses of biotin will affect this assay

 

Serum

Draw blood in a gold-top (serum separator) gel tube. Label the specimen with the patient’s name (first and last), date of birth, date and time of draw, phlebotomist’s initials, and as serum. Spin down and send 1 mL of serum refrigerated.

CPT Codes

84481

Method

Electrochemiluminesence Immunoassay

Useful For

Free triiothyronine (T3) is a second- or third-level test of thyroid function; it provides further confirmation of hyperthyroidism, supplementing the tetraiodothyroxine (T4), sensitive tyrotropin (sTSH) and total T3 assays

 

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

 

Monitoring thyroid hormone replacement therapy